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Crossbow & Scope Query


buckfever1974

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Morning guys.

We had a very difficult year with one of our crossbows as it related to being able to get it sighted in and keeping in that way for any real length of time. Range time in season meant lost time on stand as it were because of our schedules. Simon Peters was great about helping us out on walk-in visits to get things taken care of. 

I took it in in June to get everything tightened up. They did so and it seemed that "new screws" were discovered coming loose several times. It was difficult to say whether we were having a scope problem or a screw issue each time out until we got it into the shop. The crossbow, when we got it was purchased a couple years ago from eBay and ready for easy assembly. Anyway, I do have some concern over any of the screws having been stripped. I'm not sure that the scope itself is a problem because when we do shoot it's not like the groupings are bad.

I am thinking about having a shop break it down and reassemble everything, including the scope mount and rings using lock tight. Someone mentioned "blue" locktight as it isn't as permanent. Will pro-shops like Simon Peter or NJ Bow and Reel on Rt 23 do services like that or do any of you have any other ideas to keep this crap from shifting every time out.

BTW. I bought one of those Plano Manta hard crossbow cases that you can form fit to the crossbow so it is protected in my opinion during transport.

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I use blue locktite (non permanent lock) on all my screws to prevent vibration backing them out or loosening.

Definitely a good idea, and in fact a lot of the stuff I get (even non archery related) has been coming with loctite on the threads...so it's pretty common practice.

 

As far as keeping things in tune on a crossbow, that's always a challenge.

It's one of the reasons I chose Excalibur and their recurve design.  It's simple tuning, one string.  Maintain brace height and the "tune" stays true.

With compound designs (just like compound vertical bows), you have cam timing and sync to consider at all times along with brace height.  So it's just more variables.

With the recurve design, all you need is a stringer to alter the brace height.

With a compound design, you (usually) need a press of some sort to relieve the pressure for adjustment.

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As far as keeping things in tune on a crossbow, that's always a challenge.

It's one of the reasons I chose Excalibur and their recurve design.  It's simple tuning, one string.  Maintain brace height and the "tune" stays true.

With compound designs (just like compound vertical bows), you have cam timing and sync to consider at all times along with brace height.  So it's just more variables.

With the recurve design, all you need is a stringer to alter the brace height.

With a compound design, you (usually) need a press of some sort to relieve the pressure for adjustment.

 

These weapons are high end enough that you shouldn't have to worry about them on each trip.  

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Well tuning wise, not every day or every trip...but you do need to keep an eye on it as strings stretch (thereby changing the tune) no matter what a string manufacturer says.

The tuning "change" might not be that significant, not even enough to impact hunting accuracy up to a certain distance...but if you are shooting longer distances it can make a big difference.

 

Vibration and screw loosening wise, that really boils down to how much you shoot.

With compounds if you have to discharge your bow every day you hunt, things can certainly loosen up on you.

Another benefit to the recurve design in that you can let it down after every hunt.

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one thing that screws up accuracy is when you cock the xbow.  if you don't maintain exact equal pressure on your draw rope, it will shoot either right or left.  one of the reasons 10 point crossbows shoot really well is there cranking accudraw system.

 

Yes very true.  Cocking aids will definitely increase accuracy.  Excalibur has them as well as an add-on.  For general hunting accuracy say 50 yards and under, I don't find it to be "required" by any means.  Drawing by hand (being mindful of using equal pressure) is usually sufficient to get pretty good accuracy 1-2"@50 yards.

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but you do need to keep an eye on it as strings stretch

 

 

  True^^.. I buy pre stretched.. Takes to many shots to stretch one.. Like 50 or more.. Another thing, I think a bad limb may be suspect.. Perhaps dry fired to many times.. Buy used u gamble.. You may have lost on that roll..

:D

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True^^.. I buy pre stretched.. Takes to many shots to stretch one.. Like 50 or more.. Another thing, I think a bad limb may be suspect.. Perhaps dry fired to many times.. Buy used u gamble.. You may have lost on that roll..

Was not bought used. Brand new but on eBay. Comes as a kit in just two main pieces and the foot stirrup.

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  • 2 months later...

I realize this is an old thread and hope you have sorted out your bow by now, but just in case, lets look at the bow and the assembly of it out of the box. Most bows sit in boxes waiting to be sold, so what happens is that strings creep out of tune from the factory.

 

I assume it's a compound crossbow.

 

1. Mount the riser to the rail and use blue loctite

 

2. Check that the cams are in sync with each other and that the brace height is proper before even firing your first shot, if not adjust the cables and or string to bring the bow into tune. Mark your cams with a pencil for future reference, also mark your rail with a Sharpie to give you a visible reference point for your brace height on the rail if its' not scribed with one already. What these marks do for you is let you know if your bow has come out of tune over a period of time... All Strings and Cables stretch.. No matter what a string maker says, even pre stretched strings will stretch a bit but less that non pre stretched. So it is important to get the bow in tune and make your visible marks on the cams and rail as reference points.

 

3. Mounting the rings. Good rings are always advisable. Sometimes when buying a "kit" package the manufacturer does not always supply the best accessories with their packages. However, we will assume that your rings are good enough.. Place your bow on a very stable platform. I use a Caldwell field pod when setting up my Xbows. Get the bow level before you proceed and somehow make sure it stays level... Loose fit your rings to the rail and put your scope on the rings, I say loose fit because at this point we are checking eye relief. If your eye relief is good, take off the scope and now mount your rings to the rail using the blue loctite.

 

4. Mounting the scope. Here is were we need to be very anal in our process to ensure a proper alignment of the scope to the rings and that the scope cross hairs are square to the rail. My process consists of me using three levels. I mount a level on my front end to ensure it is level, then I place another level on the rail, and the third level is placed on top of the scope if the caps are flat, If your scope does not have flat adjustment caps the first two levels will get you there. Then I place the scope rings on top of the scope and lightly snug them up. Adjust your scope for the best eye relief now. Once eye relief has been achieved, now check your cross hair through the scope. You might have to turn your scope tube a bit either way to achieve a proper sight picture with regards to your cross hair and rail being square. Once the cross hairs are plum and true, now you can tighten down on your rings to mount the scope up... remember this: Most supplied rings are made of aluminum but are supplied with steel screws so be careful as you tighten them... So, again use the blue loctite on each screw and slowly tighten your ring screws a little bit on each screw at a time.. You want them to apply equal pressure to each screw as you tighten.. Keep in mind there is no reason to Gorilla tighten these screws because the blue loctite will hold them tight..

 

5. Now lets assume that the rail and scope/rings are set up right and your cross hair is square to the rail, let the bow sit overnight so that the loctite has time to set up nice and solid. This is important because if the loctite has not dried propery, screws can and will come loose throwing off your previous efforts.

 

6 Arrows.. Here is one of the most important components of your crossbow. With a crossbow, you don't have a rest to tune your arrows to the bow, so it is Extremely important to have the best arrow for your bow. With the crossbow the arrow rides the rail/rest if you will on the shot until it clears the rail. The rail is fixed and cannot be adjusted so it acts like a launch pad. If your arrows are marginal in spine ( on the weak side ), they will chatter on the rail and will not group consistently. This will be very obvious when you shoot broad heads... Field points never tell the tale. You sight in with them but when you switch over to a broad head you will notice immediately.  So my advice on arrows is to buy the stiffest and straightest arrows you can get for your bow.. Some may say that they don't need to be the straightest but when you fire your bow, try to imagine the forward pressure applied to the back of the shaft and how that can affect an arrow with a straightness tolerance that is less than desirable ( think Walmart bucket arrows..lol ).. Ideally you want an arrow with a tolerance of .001, you can get by with an .003 straightness tolerance but .001 is ideal..

 

7. Broad heads... These are a personal decision. When mounting a broad head to a shaft, you want that arrow/head combo to spin so clean that you cannot detect any wobble what so ever. You will probably have to bounce one head from shaft to shaft until you get the head/arrow combo to spin clean. Repeat this step until you have all your broad heads mounted. No big deal.. Here is another step where I get anal about my arrows and heads... I like to make sure that my fletching line up with my blades.. Here again guys will tell you it's not necessary, in my opinion it is because I feel that if the blades line up with the vanes they are not competing with the vanes to steer the arrow, and in addition it is one less variable I need to worry about if  I run into a tuning issue.

 

8. Proper basic shooting skills.... I will assume you are well practiced in shooting form so I will leave it at that..

 

9. Crossbow maintenance... you need to periodically check all your screws for tightness, keep a visual inspection on those pencil marks on your cams and scope, monitor your brace height via your sharpie mark, keep your cables and string waxed. Do not wax the center serving on your string with bow wax because it can gum up your trigger assembly and also foul your rail with tacky wax. Lube your rail sparingly with the proper rail lube. This will also condition your center serving for a longer life span.

 

Crossbows are far from out of the box hunting ready. No matter what you paid for your bow, whether you paid $300.00 or $2500.00 for your bow, realize it is a high powered weapon and needs to be treated as such in regards to the power it generates and the tune needed for it be  and maintain accuracy. They do not behave like a vertical bow because of the sudden violent launch of the string on a short bolt.

 

Hopefully this can be a tuning aid for others as well that may not know how to set up a crossbow..

 

Well that's all I can think of for now. If you have any questions, fire away.

 

Good luck,

Ed

Edited by BowTechExperience
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I realize this is an old thread and hope you have sorted out your bow by now, but just in case, lets look at the bow and the assembly of it out of the box. Most bows sit in boxes waiting to be sold, so what happens is that strings creep out of tune from the factory.

 

I assume it's a compound bow.

 

1. Mount the riser to the rail and use blue loctite

 

2. Check that the cams are in sync with each other and that the brace height is proper before even firing your first shot, if not adjust the cables and or string to bring the bow into tune. Mark your cams with a pencil for future reference, also mark your rail with a Sharpie to give you a visible reference point for your brace height on the rail if its' not scribed with one already. What these marks do for you is let you know if your bow has come out of tune over a period of time... All Strings and Cables stretch.. No matter what a string maker says, even pre stretched strings will stretch a bit but less that non pre stretched. So it is important to get the bow in tune and make your visible marks on the cams and rail as reference points.

 

3. Mounting the rings. Good rings are always advisable. Sometimes when buying a "kit" package the manufacturer does not always supply the best accessories with their packages. However, we will assume that your rings are good enough.. Place your bow on a very stable platform. I use a Caldwell field pod when setting up my Xbows. Get the bow level before you proceed and somehow make sure it stays level... Loose fit your rings to the rail and put your scope on the rings, I say loose fit because at this point we are checking eye relief. If your eye relief is good, take off the scope and now mount your rings to the rail using the blue loctite.

 

4. Mounting the scope. Here is were we need to be very anal in our process to ensure a proper alignment of the scope to the rings and that the scope cross hairs are square to the rail. My process consists of me using three levels. I mount a level on my front end to ensure it is level, then I place another level on the rail, and the third level is placed on top of the scope if the caps are flat, If your scope does not have flat adjustment caps the first two levels will get you there. Then I place the scope rings on top of the scope and lightly snug them up. Adjust your scope for the best eye relief now. Once eye relief has been achieved, now check your cross hair through the scope. You might have to turn your scope tube a bit either way to achieve a proper sight picture with regards to your cross hair and rail being square. Once the cross hairs are plum and true, now you can tighten down on your rings to mount the scope up... remember this: Most supplied rings are made of aluminum but are supplied with steel screws so be careful as you tighten them... So, again use the blue loctite on each screw and slowly tighten your ring screws a little bit on each screw at a time.. You want them to apply equal pressure to each screw as you tighten.. Keep in mind there is no reason to Gorilla tighten these screws because the blue loctite will hold them tight..

 

5. Now lets assume that the rail and scope/rings are set up right and your cross hair is square to the rail, let the bow sit overnight so that the loctite has time to set up nice and solid. This is important because if the loctite has not dried propery, screws can and will come loose throwing off your previous efforts.

 

6 Arrows.. Here is one of the most important components of your crossbow. With a crossbow, you don't have a rest to tune your arrows to the bow, so it is Extremely important to have the best arrow for your bow. With the crossbow the arrow rides the rail/rest if you will on the shot until it clears the rail. The rail is fixed and cannot be adjusted so it acts like a launch pad. If your arrows are marginal in spine ( on the weak side ), they will chatter on the rail and will not group consistently. This will be very obvious when you shoot broad heads... Field points never tell the tale. You sight in with them but when you switch over to a broad head you will notice immediately.  So my advice on arrows is to buy the stiffest and straightest arrows you can get for your bow.. Some may say that they don't need to be the straightest but when you fire your bow, try to imagine the forward pressure applied to the back of the shaft and how that can affect an arrow with a straightness tolerance that is less than desirable ( think Walmart bucket arrows..lol ).. Ideally you want an arrow with a tolerance of .001, you can get by with an .003 straightness tolerance but .001 is ideal..

 

7. Broad heads... These are a personal decision. When mounting a broad head to a shaft, you want that arrow/head combo to spin so clean that you cannot detect any wobble what so ever. You will probably have to bounce one head from shaft to shaft until you get the head/arrow combo to spin clean. Repeat this step until you have all your broad heads mounted. No big deal.. Here is another step where I get anal about my arrows and heads... I like to make sure that my fletching line up with my blades.. Here again guys will tell you it's not necessary, in my opinion it is because I feel that if the blades line up with the vanes they are not competing with the vanes to steer the arrow, and in addition it is one less variable I need to worry about if  I run into a tuning issue.

 

8. Proper basic shooting skills.... I will assume you are well practiced in shooting form so I will leave it at that..

 

9. Crossbow maintenance... you need to periodically check all your screws for tightness, keep a visual inspection on those pencil marks on your cams and scope, monitor your brace height via your sharpie mark, keep your cables and string waxed. Do not wax the center serving on your string with bow wax because it can gum up your trigger assembly and also foul your rail with tacky wax. Lube your rail sparingly with the proper rail lube. This will also condition your center serving for a longer life span.

 

Crossbows are far from out of the box hunting ready. No matter what you paid for your bow, whether you paid $300.00 or $2500.00 for your bow, realize it is a high powered weapon and needs to be treated as such in regards to the power it generates and the tune needed for it be  and maintain accuracy. They do not behave like a vertical bow because of the sudden violent launch of the string on a short bolt.

 

Hopefully this can be a tuning aid for others as well that may not know how to set up a crossbow..

 

Well that's all I can think of for now. If you have any questions, fire away.

 

Good luck,

Ed

The above thread is good info and warrants a thread of it's own with an appropriate subject heading.  The weapon in question is a crossbow and we got a new scope and we had a pro shop put teh blue lock tight on all the screws and bolts.  Also got a new string.

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