20 replies to this topic

[Gary Kehne]

I have been shooting,repairing, building, and testing longbows, recurves, and compounds for the past 55 plus years. I have also been doing crossbows for the last 40 years. I do this as a hobby, not as a business. (My wife would tell you otherwise). I deal in recurve limb crossbows only, no compounds. (Just my preference).I also build custom heavyweight arrows for bow and crossbow hunting of large & dangerous game. A year or so ago I started hearing about the "Middleton Crossbow". After doing almost a year's worth of research on Mr. Middleton and the xbows he is producing, I decided to try one out. When the DTM 375 was received, Mr. Middleton sent information stating that this crossbow was shooting 282 feet per second with an 755 grain weight arrow. My testing showed this to be a correct statement.Ichanged the stock string to a "Flemish Dyna Flight String", and tested  again using an 760 grain weight arrow. Twelve shots showed an average speed of 288 feet per second. I consider this to be somewhat impressive!I have been shooting the DTM 375 3-4 days per week and 12-20 arrows per day for the last seven weeks. I can honestly say that I have found this xbow in it's "stock form", to be a better performing xbow than any of it"s competers. But........, as with anything in "stock form", there is always room for inprovement,and the DTM 375 is no exception. Therefore, for those of you who are interested,....here is what a "tricked out" DTM 375 is capable of:......First;  The maximun poundage I can handle in a hunting situation is 250 lbs. So, no attempt was made to go beyond this poundage. I believe the xbow would produce more than this, but would require the use of a mechanical cocking aid.   Here is what has been done to the xbow: Draw length was increased to; 16 11/16 inches. This produces a draw weight of; 248.67 lbs. The string was again replaced with a flemish twist FF of my own construction as was the serving. By using this string I have aquired a 1/1000 inch clearence between the serving and arrow deck. This gives me a major reduction in friction and serving wear. The arrow deck has been heat treated and inpregnated with "Qualphite" an aerospace semi-liquid graphite.This gives me further reduction in friction, this time between the arrow and the arrow deck. The trigger assy. was totally reworked, (a seperate topic). Next is the arrow used to conduct the speed testing.   The arrow is an Easton 2215 xx78 aluminum 20 inches in length. This arrow has an insert of , Legecy 2016 - 18 1/4 inches long. This allows for the end cap, and the field point,/ broadhead insert adaptor. The arrow has also been coated with Qualphite. For purpose of this test the arrow was fletched with Fusion 2.1 inch vanes, with a 2 degree right off-set. Field point weight is, --175 grains. Total weight of the arrow is 775 grains, with 24 per cent foc.   Testing was done using two, Prochrono Machines set up in tandom. Each machine was calabrated in Jaunary ,2011. Four groups were shot, with three shots in each group, total of twelve shots. First shot group averaged:.......295.88 feet per second:   Second shot group:.....296.08 feet per second,:    Third shot group,;.....295.95 feet per second,:     Fourth shot group".....295.98 feet per second.  This is an overall average of ,  296 feet per second, which in turn equates to 150 foot pounds of kenetic energy. There is a universal requirement of having 110 foot pounds of kentic energy to harvest the largest of our land animals, (Rino & Elephant). I believe that  DTM 375 is somewhat of a mundane name for a crossbow of this caliuber. Perhaps.........  BeastMaster would be more appropriate ????????   Next up,....Penetration Testing, Which Broadhead will perform the best ????   (Sometime in May).

[CBRon]

Gary,  WOW That is some serious power.  Did you use a shim under the riser, and a spacer between the riser and rail and redrill the holes ?  Thanks  Ron

[Gary Kehne]

To: CBRon,   I shimmed the limbs.         GK

[agingcrossbower]

Mercy Gary, your ready for most anything. Can't wait to hear about your upcoming trip to africa while using that beast master. Could you add a pic or two?

[CBRon]

Gary,  thanks ,  But how did you get the string off the deck ?

[Gary Kehne]

CBRon:............   My using a much smaller diameter string, and serving. String and serving material used is a "trade secret" at this time. Much more testing has to be done before information is given to the general public,sorry.           GK

[CBRon]

Gary, That must a thin serving. I like my servings about .160"  it puts the string closer to the center of the nock, I have found this to be better for consistant accuracy. But your setup does give more speed, less friction , and probably less serving wear. Thanks  Ron

[deerboy]

Gary Kehne, on 18 April 2011 - 11:49 AM, said:

I have been shooting,repairing, building, and testing longbows, recurves, and compounds for the past 55 plus years. I have also been doing crossbows for the last 40 years. I do this as a hobby, not as a business. (My wife would tell you otherwise). I deal in recurve limb crossbows only, no compounds. (Just my preference).I also build custom heavyweight arrows for bow and crossbow hunting of large & dangerous game. A year or so ago I started hearing about the "Middleton Crossbow". After doing almost a year's worth of research on Mr. Middleton and the xbows he is producing, I decided to try one out. When the DTM 375 was received, Mr. Middleton sent information stating that this crossbow was shooting 282 feet per second with an 755 grain weight arrow. My testing showed this to be a correct statement.Ichanged the stock string to a "Flemish Dyna Flight String", and tested  again using an 760 grain weight arrow. Twelve shots showed an average speed of 288 feet per second. I consider this to be somewhat impressive!I have been shooting the DTM 375 3-4 days per week and 12-20 arrows per day for the last seven weeks. I can honestly say that I have found this xbow in it's "stock form", to be a better performing xbow than any of it"s competers. But........, as with anything in "stock form", there is always room for inprovement,and the DTM 375 is no exception. Therefore, for those of you who are interested,....here is what a "tricked out" DTM 375 is capable of:......First;  The maximun poundage I can handle in a hunting situation is 250 lbs. So, no attempt was made to go beyond this poundage. I believe the xbow would produce more than this, but would require the use of a mechanical cocking aid.   Here is what has been done to the xbow: Draw length was increased to; 16 11/16 inches. This produces a draw weight of; 248.67 lbs. The string was again replaced with a flemish twist FF of my own construction as was the serving. By using this string I have aquired a 1/1000 inch clearence between the serving and arrow deck. This gives me a major reduction in friction and serving wear. The arrow deck has been heat treated and inpregnated with "Qualphite" an aerospace semi-liquid graphite.This gives me further reduction in friction, this time between the arrow and the arrow deck. The trigger assy. was totally reworked, (a seperate topic). Next is the arrow used to conduct the speed testing.   The arrow is an Easton 2215 xx78 aluminum 20 inches in length. This arrow has an insert of , Legecy 2016 - 18 1/4 inches long. This allows for the end cap, and the field point,/ broadhead insert adaptor. The arrow has also been coated with Qualphite. For purpose of this test the arrow was fletched with Fusion 2.1 inch vanes, with a 2 degree right off-set. Field point weight is, --175 grains. Total weight of the arrow is 775 grains, with 24 per cent foc.   Testing was done using two, Prochrono Machines set up in tandom. Each machine was calabrated in Jaunary ,2011. Four groups were shot, with three shots in each group, total of twelve shots. First shot group averaged:.......295.88 feet per second:   Second shot group:.....296.08 feet per second,:    Third shot group,;.....295.95 feet per second,:     Fourth shot group".....295.98 feet per second.  This is an overall average of ,  296 feet per second, which in turn equates to 150 foot pounds of kenetic energy. There is a universal requirement of having 110 foot pounds of kentic energy to harvest the largest of our land animals, (Rino & Elephant). I believe that  DTM 375 is somewhat of a mundane name for a crossbow of this caliuber. Perhaps.........  BeastMaster would be more appropriate ????????   Next up,....Penetration Testing, Which Broadhead will perform the best ????   (Sometime in May).

Would really appreciate seeing some pics!

[MiddletonDTM375]

Gary fantastic post the detail in your test's and what you are accomplishing is great to read.  If you get a chance I would love to hear anything you have on trajectory, ie. 775 grain arrow zero @ 20 or what ever you feel is optimal 10, 20, 30 ,40.  Keep up the work I know many of the viewers read and appreciate the information.

Derrick Middleton

[Lightfoot]

Good to see you are back Derrick. Gary has supplied me with three arrows for testing, 725,825,925 grains respectively. Since you are close by, why not do a little testing yourself and make a few vids for all?

I'd welcome a chance to visit your factory and help you with those tests LOL. The arrows are all flat nocks and all I have to test them is an Excal Paradox.

L.

MiddletonDTM375, on 24 April 2011 - 10:37 PM, said:

Gary fantastic post the detail in your test's and what you are accomplishing is great to read.  If you get a chance I would love to hear anything you have on trajectory, ie. 775 grain arrow zero @ 20 or what ever you feel is optimal 10, 20, 30 ,40.  Keep up the work I know many of the viewers read and appreciate the information.

Derrick Middleton

[MiddletonDTM375]

Spoke with Gary he has developed equipment to hold a bow and with provide details when he gets a chance.

[Lightfoot]

Gary Kehne, on 18 April 2011 - 11:49 AM, said:

I have been shooting,repairing, building, and testing longbows, recurves, and compounds for the past 55 plus years. I have also been doing crossbows for the last 40 years. I do this as a hobby, not as a business. (My wife would tell you otherwise). I deal in recurve limb crossbows only, no compounds. (Just my preference).I also build custom heavyweight arrows for bow and crossbow hunting of large & dangerous game. A year or so ago I started hearing about the "Middleton Crossbow". After doing almost a year's worth of research on Mr. Middleton and the xbows he is producing, I decided to try one out. When the DTM 375 was received, Mr. Middleton sent information stating that this crossbow was shooting 282 feet per second with an 755 grain weight arrow. My testing showed this to be a correct statement.Ichanged the stock string to a "Flemish Dyna Flight String", and tested  again using an 760 grain weight arrow. Twelve shots showed an average speed of 288 feet per second. I consider this to be somewhat impressive!I have been shooting the DTM 375 3-4 days per week and 12-20 arrows per day for the last seven weeks. I can honestly say that I have found this xbow in it's "stock form", to be a better performing xbow than any of it"s competers. But........, as with anything in "stock form", there is always room for inprovement,and the DTM 375 is no exception. Therefore, for those of you who are interested,....here is what a "tricked out" DTM 375 is capable of:......First;  The maximun poundage I can handle in a hunting situation is 250 lbs. So, no attempt was made to go beyond this poundage. I believe the xbow would produce more than this, but would require the use of a mechanical cocking aid.   Here is what has been done to the xbow: Draw length was increased to; 16 11/16 inches. This produces a draw weight of; 248.67 lbs. The string was again replaced with a flemish twist FF of my own construction as was the serving. By using this string I have aquired a 1/1000 inch clearence between the serving and arrow deck. This gives me a major reduction in friction and serving wear. The arrow deck has been heat treated and inpregnated with "Qualphite" an aerospace semi-liquid graphite.This gives me further reduction in friction, this time between the arrow and the arrow deck. The trigger assy. was totally reworked, (a seperate topic). Next is the arrow used to conduct the speed testing.   The arrow is an Easton 2215 xx78 aluminum 20 inches in length. This arrow has an insert of , Legecy 2016 - 18 1/4 inches long. This allows for the end cap, and the field point,/ broadhead insert adaptor. The arrow has also been coated with Qualphite. For purpose of this test the arrow was fletched with Fusion 2.1 inch vanes, with a 2 degree right off-set. Field point weight is, --175 grains. Total weight of the arrow is 775 grains, with 24 per cent foc.   Testing was done using two, Prochrono Machines set up in tandom. Each machine was calabrated in Jaunary ,2011. Four groups were shot, with three shots in each group, total of twelve shots. First shot group averaged:.......295.88 feet per second:   Second shot group:.....296.08 feet per second,:    Third shot group,;.....295.95 feet per second,:     Fourth shot group".....295.98 feet per second.  This is an overall average of ,  296 feet per second, which in turn equates to 150 foot pounds of kenetic energy. There is a universal requirement of having 110 foot pounds of kentic energy to harvest the largest of our land animals, (Rino & Elephant). I believe that  DTM 375 is somewhat of a mundane name for a crossbow of this caliuber. Perhaps.........  BeastMaster would be more appropriate ????????   Next up,....Penetration Testing, Which Broadhead will perform the best ????   (Sometime in May).

Hi Gary. Just to let you know I've had a little fun with the heavyweights you sent me for the moon nocks. The two vane one my bow didnt like at all and was a flyer so will need to be refletched. My bow however seemed to like the other two (heavier?) arrows and I've had fun with the armor piercing. While shooting 350-400 grains regularly the heavy weights do seem to have a little more penetration even at my low speeds.

Been wanting to build a heavier pull bow but have one more light pull build to do. Cronied about a month ago I can get 175fps with a 400 grain and 50lbs pull - thats pulling a full eight grains per lb of pull! The equivelent for your DTM375 bow is a whopping 2000 grains!  

Doing the math on the heavy weights you sent me is at 15 grains per lbs of pull or thereabout.

So with the arrows, I'd like to have a few very lightweight ones - perhaps 300 grains total to bring it down to a more reasonable 6 grains per lbs of pull and get it rechronied. I'd be happy with pulling 250fps considering - it after all a "house" bow LOL.

(BTW - the low power design is not for hunting but for power/effeciency research)

Edited by Lightfoot, 08 June 2011 - 10:05 AM.

[Lightfoot]

Hey Bud. Got a new build done and Gary has kindly built me a pile of arrows for testing. They range all the way from about 275 grains through 400 for the lightweights and three heavyweights up to about 1300 grains. Friggin awesome.

The new build is wider and faster. I added two additional power settings, and built it with enough room for 1.5' spring, or, two springs running parralell. Dramatic increase in speeds with double the penetration, so Im hoping Im pretty close to 300fps now with the second spring. The lowest power setting way faster than what you tested, and I still have about another 40 degrees of rotation I havent tapped yet.

Be cool if you could pop by and take it for some chrony testing. I still have a few manufacturers nibbling so getting it past 300fps with under a hundred lbs pull outta wake them up. BTW, I also had a second "riser" made up for the DTM375 and thought I'd see what a "recurve" (non compounding) model will do.

It should be ready for testing end of month. I picked up an old Jennings Devastator off ebay for a railess build.

I thought it might also be cool be bolt a Middleton riser and limbs to it and give it 17 or 17.5 draw or some of those experimental limbs you have. I love to design n build stuff....
  

MiddletonDTM375, on 27 April 2011 - 08:17 AM, said:

Spoke with Gary he has developed equipment to hold a bow and with provide details when he gets a chance.

[phil abrahams]

The Middleton recurve crossbow really has set new power standard's for all crossbow's.By using more aerodynamic limb's this is a good step in the right direction as the faster an object is travelling so is the greater the resistance to that speeding object.Also getting the composite mix for limb's that can handle these very high speed and power level's is not an easy task and to be hitting out 150 ft lbs of K.E is truly a remarkable feat of engineering.I have a lot of respect for Middleton crossbow's and if i was in the market to purchase a crossbow then i would be getting myself a Middleton as Derrick is clearly passionate about the way his bow's perform and he know's how to make recurve limb's like no other.I myself have overcome high resistance with my design's and it doe's pay dividend's.Gary your work is very interesting and fascinating and i alway's find experimenting with different idea's great fun and there is alway's room for improvement i think with all kind's of thing's and taking thing's to the extreme by finer tuning is the way forward for all i truly believe as it keep's thing's more interesting and fascinating and the reward's are well worth all the hard work and dedication.

Edited by phil abrahams, 12 July 2011 - 06:16 PM.

[Lightfoot]

Gary Kehne, on 19 April 2011 - 11:05 AM, said:

CBRon:............   My using a much smaller diameter string, and serving. String and serving material used is a "trade secret" at this time. Much more testing has to be done before information is given to the general public,sorry.           GK

HI Gary. I understand all about the testing part. Testing is such fun I swear it will never end nor will I ever be satisfied with results no matter how good. Thanx for those custom lightweights. I did manage to remove the flat end insert and replace with a lighter plastic moon nock for total weight of 246 grains. I also took a HOrton carbon and shortened it down some using one of the lightweight target points for a 308 weight. Medium weights also were at 402, 428, 478,502.

The heavy weights you sent me for moon nocks weigh in at 788, 872, and 1280 respectively.

Lightweight results were that I sighted the scope in for the 428 and 487 grain arrows, and the new lightweights shot exactly three inches higher so while I dont have a chrony, I think the velocity has increased a tad or two as suspected. My new wider build has offered up some improved overall performance as well I believe.

The heavyweights acted in the opposite way with similar results. The 788 shot an inch low, the 872 about two inches low, and the 1280 about four inches low. These tests were with a single spring. I've added a second spring capacity to it since my last build.

In testing with twin springs running parralell, my targets were old romance novels my wife had finished up with and proved inadquate backstops after just a few shots. I had set them up on an old chair in the porch with what I thought was a steel faced door front and back. Went through the books with the target point piercing my front door almost all the way through so that only the very tip of the target point poked through. Needless to say I quickly curtailed my penetration testing.

It appears I must move testing to hobbit heaven (the basement) where I have a concrete backstop or get a proper target. Once the wifey spies the hole in the door I will be lucky to be allowed to shoot in the house at all. Lucky for me she hasnt seen or commented on the fridge yet haha.

Anyhow, as this is a tricked out middlton thread, I also have a torsion riser made up for the Middleton.375 which I will breath to life over the next week or so as funds allow. Since you have been more than generous in helping me with custom arrows, I hope this build to be for the heavy weight arrows or big game.

The new design challenge is to exact the same performance from 16.5" as I can from the Scorpyds 20" draw.

The Jennings Devastator bullpup railess design is a pure pleasure to work with. First I junk the heavy wide limbs and riser, then bolt on the torsion ballista kit. The result is more than I hoped for providing a very short weapon with full capability. I will have to recheck the specs on the new Gearhead pistol crossbows seen at the 2011 ATA but I think the length is about the same. VERY  compact. The riser sits midway to the front pistil grip and the trigger.

Once I have the Middleton 375 torsion all tricked out and puttng out decent numbers, I may invest in having the trigger moved forward somehow (linkage)and give it the same bullpup and length as the Jennings.

Bottom line is to say thanks Im trying to build a big game heavy arrow chucker that is torsion powered. As there are no torsion "crossbows" existing yet, there is a huge opportunity to make the record books - first deer taken by a "manuballista", first elk, first water buff, and so on.

It is one thing to design maximum effeciency for a low power design, but to have those principals work the same for a heavier pull is another. I seem to have bridged that gap, and the addition of more power is providing the rewards I was hoping for for (so far anyway).

Phil and I are alike in that we MAY have some nice and unique products the public might like, but mostly in that what we build and breathe may be best described as "alternative powered sports weaponry". So in a month or less I should have a tricked out alternative powered Middleton DTM375 torsion inswinging design for you to try out if you wish.

I still have the custom heavy weight flat end arrows you built for the Middleton 375 speed/trajectory/penetration tests, and will pass them along to Derrick should he pop by sometime.

If anyone is interested in what the bowtech 380 does with heavy arrows (moon nocks), Derrick has access to one and I'd be happy to lend him my moon nock heavyweights as long as they come back.

As for me, my next move is simply to add more power to existing design, bringing power up to 150 lbs pull gradually until I reach a desired speed with a desired arrow weight. Independant design testing and performance verification for a "recurve" or non compounding torsion based middleton design can be found by reading a ballista build blog at www.wattsunique.com

Previous speed tests have yielded results of 395fps, 5000lbs pull, 7500 grain bolt. A new design feature not yet completed should take it past 425fps. I have every confidence so far that a 200lbs pull torsion inswinging crossbow is capable of velocities of over 300fps with a 700-800 grain arrow.  IF not than pretty damn close.

So thanx to both Gary and Derrick Middleton who have helped me with much needed components and encouragement. The Middleton torsion is incredibly lightweight despite its use of solid steel in its construction so far. In a short while I will be able to showcase my "ghetto blasters" mounted on various crossbow platforms, and while not for everyone I have had more than my share of fun and adventure designing and building them for my own use and interests.

I've put aside the Scorpyd for now as its about complete, have the Jennings mock up completed and looking/feeling awesome, and the Middleton is receiving both my design attentions and what little funds/parts I have to work with now. I'll send you a little vid when the DTM375 build is completed and performance tuning completed.

The designs shown will be my more basic designs and have saved what I call patentable for myself for the time being.

And  Phil if you read this, please remember you promised me to send a demo for testing and review.

L.

[MiddletonDTM375]

Gary Kehne, on 18 April 2011 - 11:49 AM, said:

I have been shooting,repairing, building, and testing longbows, recurves, and compounds for the past 55 plus years. I have also been doing crossbows for the last 40 years. I do this as a hobby, not as a business. (My wife would tell you otherwise). I deal in recurve limb crossbows only, no compounds. (Just my preference).I also build custom heavyweight arrows for bow and crossbow hunting of large & dangerous game. A year or so ago I started hearing about the "Middleton Crossbow". After doing almost a year's worth of research on Mr. Middleton and the xbows he is producing, I decided to try one out. When the DTM 375 was received, Mr. Middleton sent information stating that this crossbow was shooting 282 feet per second with an 755 grain weight arrow. My testing showed this to be a correct statement.Ichanged the stock string to a "Flemish Dyna Flight String", and tested  again using an 760 grain weight arrow. Twelve shots showed an average speed of 288 feet per second. I consider this to be somewhat impressive!I have been shooting the DTM 375 3-4 days per week and 12-20 arrows per day for the last seven weeks. I can honestly say that I have found this xbow in it's "stock form", to be a better performing xbow than any of it"s competers. But........, as with anything in "stock form", there is always room for inprovement,and the DTM 375 is no exception. Therefore, for those of you who are interested,....here is what a "tricked out" DTM 375 is capable of:......First;  The maximun poundage I can handle in a hunting situation is 250 lbs. So, no attempt was made to go beyond this poundage. I believe the xbow would produce more than this, but would require the use of a mechanical cocking aid.   Here is what has been done to the xbow: Draw length was increased to; 16 11/16 inches. This produces a draw weight of; 248.67 lbs. The string was again replaced with a flemish twist FF of my own construction as was the serving. By using this string I have aquired a 1/1000 inch clearence between the serving and arrow deck. This gives me a major reduction in friction and serving wear. The arrow deck has been heat treated and inpregnated with "Qualphite" an aerospace semi-liquid graphite.This gives me further reduction in friction, this time between the arrow and the arrow deck. The trigger assy. was totally reworked, (a seperate topic). Next is the arrow used to conduct the speed testing.   The arrow is an Easton 2215 xx78 aluminum 20 inches in length. This arrow has an insert of , Legecy 2016 - 18 1/4 inches long. This allows for the end cap, and the field point,/ broadhead insert adaptor. The arrow has also been coated with Qualphite. For purpose of this test the arrow was fletched with Fusion 2.1 inch vanes, with a 2 degree right off-set. Field point weight is, --175 grains. Total weight of the arrow is 775 grains, with 24 per cent foc.   Testing was done using two, Prochrono Machines set up in tandom. Each machine was calabrated in Jaunary ,2011. Four groups were shot, with three shots in each group, total of twelve shots. First shot group averaged:.......295.88 feet per second:   Second shot group:.....296.08 feet per second,:    Third shot group,;.....295.95 feet per second,:     Fourth shot group".....295.98 feet per second.  This is an overall average of ,  296 feet per second, which in turn equates to 150 foot pounds of kenetic energy. There is a universal requirement of having 110 foot pounds of kentic energy to harvest the largest of our land animals, (Rino & Elephant). I believe that  DTM 375 is somewhat of a mundane name for a crossbow of this caliuber. Perhaps.........  BeastMaster would be more appropriate ????????   Next up,....Penetration Testing, Which Broadhead will perform the best ????   (Sometime in May).

Gary would like to know if Qualphite compares with Dupont teflon on a friction scale.

[Mick]

MiddletonDTM375, on 21 October 2011 - 06:10 AM, said:

Gary would like to know if Qualphite compares with Dupont teflon on a friction scale.

I Googled "Qualphite" and the only entry Google found on the entire web was this CBN thread.  So who makes "Qualphite"?

[Terminal-operator]

Mick, on 02 November 2011 - 04:44 PM, said:

I Googled "Qualphite" and the only entry Google found on the entire web was this CBN thread.  So who makes "Qualphite"?

                       NASA!!!!

[MLN1963]

Did G K drop off the map? Nothing from him in almost a year.

[TeamCrooks]

You guys are funtastic.  You're like the "Big Bang Theory" of crossbowdom.  Gotta love it.  And I mean that in the very best way!  Please keep doin' whatcha do, and sharing it with the rest of us!