34 replies to this topic

[xbow755]

Hi All,
Below are the steps used to perform the Upper Weaver Rail Modification on the PSE TAC Series Crossbows:

PSE TAC15/15i Weaver Rail Modification Process (Step-by-Steps)
The following process outlines the simple steps to modify the Weaver Scope Rail on the PSE TAC series crossbows.
Included below is a photograph of my PSE TAC15i Crossbow with the modification completed. It shows the crossbow in a fully loaded position, using a three vane arrow with the cock vane positioned at 12:00.

This modification was designed to prevent vane clearance problems caused by the arrows vanes from coming in contact with the underneath side of the crossbows Weaver Style Upper Rail during the launch process. This interference can be clearly observed during the cranking or load operation, if you watch carefully. Generally, one or more of the TAC15 arrows vanes will come in contact with the underneath side of the Weaver Rail and sometimes the arrows nocks will hit against this same rail as the crossbow is being brought into a fully loaded position. This contact is also taking place during the launch once the trigger is pulled, but then it takes place so fast that it can’t be tracked with the human eye. This causes a disruption to obtaining a clean launch of the arrows shaft. It has been identified as a one of the causes for grouping variations due to inconsistent launch performance.
I can now shoot either PSE TAC15 Arrows in a four fletch (60 x 120 degree position), 3” vanes, straight with no offset  or a standard three fletch configuration (3 x 120 degrees), 3” vanes, 2 degree left straight offset, with excellent performance results from either.
This does not mean that one can shoot either arrow type with no changes to your crossbow. Any type of arrow change will alter your paper tuning results. The crossbow must be re-tuned to the particular arrows you are using in order to achieve optimal flight performance.  Elevation changes are not required, but windage tuning is usually necessary as you change from a three fletch to a four fletch arrow.

file:///C:/Users/Jon/AppData/Local/Temp/msohtmlclip1/01/clip_image002.jpg
Look carefully at the angle of the cut rail and the smooth edge created.

Modification Step-by-Steps:

Step 1. Turn the PSE TAC15/15i crossbow upside down and place on a soft towel or padded surface so it can be worked on without scratching or bumping your scope or other top end parts.  Observe closely the underneath side of the Upper Weaver Rail. Pay particular attention to the bevel on the underside of the front edge of this rail. Also, make note of the angle from the top edge to the bottom edge of the front edge of your rail.  This angle and the bevel are so that your arrows nocks do not catch on the edge of the rail during the cocking and loading of the crossbow.

Step 2.  Turn the crossbow back to its normal upright position on a safe work surface. I would still recommend the use of a towel or soft material to prevent any scratches while working.  Using a very fine toothed hacksaw you will need to measure and remove exactly 2.75” (2 ¾” inches) from the forward edge of your upper Weaver Rail.  Make sure you angle (miter) your cut, so that it’s at a reward 45 degrees or better, to emulate the factory bevel that was on the forward edge that you just examined in step 1.   You can also use a fine toothed metal cutting blade on a sawzall or other metal cutting tools.

Step 3.  Once you have the initial cut completed, next you must file down and remove any excess metal from the underneath side of the front edge of the Weaver Rail. This is to smooth the front edge underneath surface. To perform this work, remove your scope and or HHA Optimizer Speed Dial and scope from the upper Weaver Rail and then turn the crossbow upside down so the bottom is now face up.  I used a Dremel tool with a small grinding wheel and was easily able to smooth the front edge and also create the same type of bevel as provided by the manufacturer. If a Dremel Tool is not available, a medium to fine metal file should work, but it will take a bit more filing work to achieve the same results.

Step 4.  Once all filing or grinding work has been completed and you’re satisfied with the results, turn the crossbow over and load an arrow in the same manner as you normally would.  As you move through the  cranking process pay particularly close attention to the arrows nock as it passes your new Weaver Rails underneath side leading edge. Make sure that your edge has been rounded and smoothed so the nock cannot grab this edge and it’s forced underneath. Make sure that you’ve tapered your underneath side of the rail to support a smooth transition to the fully loaded position.  In the event anything is not smooth go back to step 3 and finish grinding or smoothing the cut edge or the underneath side bevel.

Step 5.  Once all grinding or filing work has been completed and you’re comfortable with the load operation, you will need to mask off all areas of your crossbow that were not cut or grinded, with some masking tape or newspaper and tape.  This is so you can paint or touch up the areas that you just cut or ground down.  Using a Rusto-leum or similar “Flat Black” metal spray finish paint, spray the areas that need to be touched back up.  This will provide a good protective finish on the parts that were just exposed during the above work.  I used two light coats on my TAC15i and can’t tell the difference from the rest of my stock.  I know that one or two other members who’ve performed this modification mentioned they had taken their crossbow in and had somebody replace the factory original powder coat.  I haven’t found it necessary, but the choice is yours.

Step 6.  Replace your HHA Optimizer Speed Dial and / or Scope and resume shooting as usual. Remember, if shooting 3 fletch configuration your nock orientation must be changed to cock feather up.

Regards,

Xbow755

[LegendInMyOwnMind]

xbow755, on 28 February 2012 - 01:19 AM, said:

Hi Twanger,
I guess that all depends on how you measure a group?  I've seen way to many people display shot groups in pictues they've posted. I consider a four inch group from my aim point, which is usually a 3/4" florescent green dot that I place on my target at the specified distance. If the group is 5 inches to the left of that dot and the arrows have a four inch spread, that is not a four inch group in my book. I'm talking about drawing a four inch circle around that green dot and keeping everything inside that circle. Try it at 80 yards and then let me know how you're doing?

The Whisker Biscuit will begin to wear the bristles on your Whisker Biscuit and your elevations will begin to change ever so slowly over time. As you continue, you will need to make a very minor adjustment in your elevations especially for the longer distance shots. When this occurs, if you take a look at the hole in the center o the Whisker Biscuit, you'll notice that it's no longer round. Instead it becomes a large oval. This oval will continue to elongate as more wear and time causes this to take place.

Within 1000 shots or so, you'll be forced to change to a new Whisker Biscuit. Long before this takes place, you'll learn that your paper tuning exercise went out the window, becuae your original elevation adjustments are no longer even close to what they were when you originally paper tuned your crossbow.

When you change to a new Whisker Biscuit, you are forced to go back and re-papertune your crossbow because all alignments from the original rest are gone. That's both widage and elevation adjustments.  Since you've been adjusting your elevations over the months to compensate for the verticle wear on the Whisker Biscuits whiskers, you must now re-sight and adjust your elevation settings back to a new alignment.

I don't know how often you want to repeate this process or how much work you're willing to do, but that's what you're in for with that style of a rest. Between the occasional arrow fliers you'll get and the wear and tear factor, many of us would much prefer to put some extra work in on the front side to eliminate the problems and maintain better long term stability.

Just one mans thoughts!

Xbow755

Good stuff! I'll admit I'm a neophyte when it comes to crossbows. I learn quickly though. I've been bow/rifle/ML hunting for years. You have to be willing to learn something new. This is a great help and I believe this is what forums are supposed to be all about! Btw, this all makes perfect sense. Keep it coming!

Edited by LegendInMyOwnMind, 28 February 2012 - 09:18 AM.

[xbow755]

Your questions and comments are well thought out, so they are appreciated.  I couldn't agree more about your comments that this is what forums were designed for.

We address many of the technical concerns and problems experienced by owners.  My belief is that designers are the ones who origiate new ideas, but engineers take anything that's been invented and use their skills to improve on an idea.  Some of the members of this forum in particular have spent the past two years doing just that!  The original TAC15 / 15i concept was unique in the world of crossbows. It had some god points and some flaws, but we've been isolating and analyzing the flaws for quite awhile. We've created upgrades for most, if not all of the weak points. We took a good product and made it much better!

Regards,

Xbow755

[topgun80]

OK, I put the QAD HDX dropaway rest on today and now the thing won't paper tune. I've move the rest the full range of it's adjustability with no effect whatsoever. No matter how high/low the rest is I still get a tail low tear. Any ideas?

[pacrossbow_]

topgun80, on 09 March 2012 - 12:16 AM, said:

OK, I put the QAD HDX dropaway rest on today and now the thing won't paper tune. I've move the rest the full range of it's adjustability with no effect whatsoever. No matter how high/low the rest is I still get a tail low tear. Any ideas?

How about posting a pic of the rest maxed out on height adjustment so we can see that to start...

[topgun80]

I just set it back height wise to hit where my whisker bisquit was hittng with bullet holes. If the arrow was hitting the rest it would kick the back end up for a high tear wouldn't it? I thought maybe the rest was too slow to get out of the way, after all they were not made for 26" arrows at over 400fps.

[bski]

The shape of aerovanes actually start to spin when they go through the biscuit!!!

[topgun80]

bski, on 10 March 2012 - 06:18 PM, said:

The shape of aerovanes actually start to spin when they go through the biscuit!!!

I guess that must be a good thing then because the bisquit shot a lot better than the QAD

[pacrossbow_]

topgun80, on 09 March 2012 - 12:16 AM, said:

OK, I put the QAD HDX dropaway rest on today and now the thing won't paper tune. I've move the rest the full range of it's adjustability with no effect whatsoever. No matter how high/low the rest is I still get a tail low tear. Any ideas?

topgun80, on 10 March 2012 - 03:43 PM, said:

I just set it back height wise to hit where my whisker bisquit was hittng with bullet holes. If the arrow was hitting the rest it would kick the back end up for a high tear wouldn't it? I thought maybe the rest was too slow to get out of the way, after all they were not made for 26" arrows at over 400fps.

You said you ran out of adjustment, which is it; did you just set it where the whisker biscuit height was or adjust it until you ran out of height?

They are 2 totally different style rests and the height of one doesn't mean it will be the height of the other.

The bow is not too fast for the rest, I contacted QAD several weeks ago in regards to buying other items and talked about the QAD on TACs. They said the rest drops before the fletchings even come close.  Feel free to contact QAD personally if you want to verify.

ETA:

I believe you now have it set back to the whisker biscuit height so a pic wouldn't matter, correct?

You can always take the crossbow to a quality archery show familiar with QAD rests and have them take a look.  Sometimes a second set of hands/eyes helps (at least it does for me sometimes)

Edited by pacrossbow_, 10 March 2012 - 08:56 PM.

[topgun80]

I no longer have access to a paper tuner, my arrows penetrate all the way through the block targets my dealer has and stick in the wall. I made some minor adjustments and all is well now, the QAD works great. My TAC15i is shooting good now with the right arrows, don't know for sure how well it's papertuned but at this point it doesn't matter, I'm happy with the results

[xbow755]

Hi topgun80,
Just so you have the information, if you should decide to purchase any targets that you can use whenever or whereever you choose, there are three targets that all work well and will stop anything you can throw at them.  two of them are for fieldpoints only and the third is for broadheads only.  Nobody makes a target that is good for both fieldpoints and broadheads because the operate on different principles.

For normal fieldpoint shooting, I prefer the the Spyderweb 2.0 targets because they are the best quality and require only two fingers to remove any shot you put into them.  their downside is they are somewhat expensive for a decent sized target.  The target I use daily and have over 3,000 shots into is the Morrell Bone Collector Outdoor Range Target.  It's almost 36" x 35" and weighs about 50lbs.
It's a bag style target and easily stops everything I've hit it with in the past year and a half.  It too has very easy arrow removal, but I can also set it up at 100 yards and it's large enough to easily shoot the long stuff.  These targets are just over $100, so if you get it locally, you don't have to pay shipping which makes them very affordable.

When shooting broadheads, it's not just density that's needed to stop your arrows, it's also largely friction because of a broadheads cutting ability.  The best target in the market for this are the Rinehart Targets.  I use the Rhinoblock XL because it's larger than all their other targets.  This is important when you're testing broadheads at 80 yards.  That's the type of thing where we don't want to take chances of missing our intended target.

Make no mistake about it, nobody makes a broadhead target that has easy arrow removal. If they tell you otherwise, they're lying!  The only two targets that I'm aware of that will stop broadheads from these crossbows are the Rinehart series targets or the "Block Black".  The Block Black doesn't carry the Rinehart replacement policy and it's even harder to remove arrows from these targets.  Rinehart will replace any target that you can shoot out within twelve months or less, so you get what you're paying for.  These targets will stop a tank because of the density and friction.  Don't make the mistake of shoting a fieldpoint arrow into it or you'll think your arrow shaft is welded to the material.

Regards,

Xbow755

[Twanger]

Jon - I don't have a picture of an 80 yard group, but do have a picture of a 100 yard group.
I didn't measure it with a tape, but believe that is something over 2 inches and under 2.5 inches.

[Twanger]

Oh... I was shooting from the white table just visible under the big cedar trees.
The 80 yard groups were smaller.

[xbow755]

100 yards. Sorta windy. Can do better...



Moved up to 90 yards......wind calmed down and I had a short window to shoot.



Shot over the chrono at the bow. 433 grain arrow at 394 fps. I moved the chrono to 99 yards and shot over it there. Same arrow 333 fps. That is only a 61 fps loss over 98 yards. 106.7 foot pounds of energy at 100 yards. Impressive! 149 foot pounds at point blank range. Unreal.

[xbow755]

Hi Twanger,
I thought you might be interested in seeing these results with the chrono statistics at the bottom.  These pictures were taken by Super 91 early last fall on a warm but slightly breezy day.
The shot groupings were achieved using a very well tuned TAC15i and all arrows had been spine tested and matched for timing and weight balanced, so this is what you get when everything is tuned in the manner I've specified in my articles.

Super 91 and I collaborated on every testing and tuning article either of us ever produced.  It's not enough to just say something works, we always did the testing and tuning first and then got around to writing the articles once we realized other owners might want to do the same things.  I don't want to sound like we did everything ourselves, because we had a lot of involvement from a number of other members who also shared their thoughts and ideas, when we were troubleshooting many of the problems that we identified fixes for.

If you look closely at the arrows used in these tests you can see that they were all four fletch 60 x 120 vane configuartions using the 3" Duravane 3D vanes.  Also, all nocks had been removed and changed to the Firenock "D" nocks.  Also, every arrow is perfectly spine matched and the nocks are all tuned to the stiff side of each arrows spine. Considering the distances being shot, I would say it's rather difficult to get any better groups.  By the way, for the record the top grouping is what I refer to as a 2.5 - 3" grouping. The 90 yard grouping is what I would typically call a one inch grouping.

I'll see about taking some additional pictures this year, that I can post for everyone, once things warm up a bit and I start doing some long distance shooting again this year, but remember that I said I don't like to post pictures of myself shooting.  People get the idea that just because I can do certain things when I'm shooting, they can accomplish a similar thing. I beleive that's a bad message because in order to achieve certain levels of shooting accuracy, it's more important how the weapon is set up and adjusted, along with environmental conditions, than who's behind the trigger. When bench resting your crossbow anybody can pull off some god shots.

There's a great u-tube video of a guy named Izzy shooting a TAC15 crossbow at 100 yards.  Izzy nails a one inch dot after only two attempts at 100 yards. Everybody who watches this video is in awe of the TAC15 and his shooting capabilities.  In reality, Izzy couldn't do much more than hit the entire target at these distances. We know this because Izzy is not a proffesssional marksman, he's a camera specialist and knows how to set up multiple camera's to rig a shot to make it appear as though he's actually performing a good long distance shot.  He shows a camera view of the target at 100 yards and then pans in for the shot. A pause and then he moves his bench to within 30 yards and resumes the video.  

Izzy has no knowledge of tuning or balancing arrows or tuning his crossbow, so anybody with just a little undertanding of arrow timing and oscillation, coupled with non indexing of ones nocks and the weight differences inherant in each shaft, all the luck in the world makes this effort impossible to achieve.  People are very blind to what's necessary to obtain optimal performance from their equipment.

Many of the guys who have been on these forums over the last year or two have learned a great deal and now understand most of this knowledge, so they now realize how much most other people don't know about what they speak.  They are the ones who are best equipt to learn from because they have real knowledge and know how to actually get the most out of their equipment.  

As you stated early on, you're new but learn fast.  Just keep reading the threads and talking to the guys on the PSE TAC forums.  You'll get there very soon.

Regards,

Xbow755