Bushmaster problems

[john_m44]

I have a preban Bushmaster A2 target with a removable carry handle, I have used two different ways to mount a scope along with 2 different scopes.
I can't get enough windage out of the scope to hit paper at 100y.

Id like to put a 204 barrel on it but Im afraid Ill be in the same boat with a new barrel.

What do you guys think the problem may be?

 

[George Az]

Does it shoot with iron sights? I have a hard time seeing such a discrepency of an upper reciever. Have you tried at 25 yards?
Did you try a different round? If your twist is one in twelve and you tried using match rounds of 77 grains - there may be a problem.

There are adjustable for windage bases, but I am having a hard time thinking you upper reciever is that crooked. I mean it could be, but then just changing your barrel isn't going to fix anything when it could be a problem with the upper. Maybe barrel nut interface with the upper reciever? So take the hanguards off and lay a straight edge down the reciever and barrel. If it is crroked, it will be noticable and you would then be off.

 

[ORD]

I have a preban Bushmaster A2 target with a removable carry handle, I have used two different ways to mount a scope along with 2 different scopes.
I can't get enough windage out of the scope to hit paper at 100y.

Id like to put a 204 barrel on it but Im afraid Ill be in the same boat with a new barrel.

What do you guys think the problem may be?

Ok...first off, is it an A2 Target (fixed, forged as a part of the upper receiver) carry handle upper or is it an A3 Target (flattop upper) with a thumbscrew-type detachable carry handle? BM made both types, but the A2 is NOT a flattop.

If it is a FIXED carry handle upper, give up now trying to mount a scope on it and if you want another AR in .204 Ruger, buy a flattop upper and start over building something that was meant to be scoped in the first place. Carry handle scope mounts, regardless of manufacturer, country of origin, etc., are just ragged ass pieces of garbage by in large. Short of bedding the damned things into the sight channel, followed closely in 2nd place of loc-titing down the damned things down with enough torque to break a pry bar, they just don't hold zero and because of variances of mfging tolerances, don't ever quite fit right and can cause just the sorts of odd and otherwise inexplicable "windage" issues you are describing with yours now.

If it is a removable carry handle setup, how about more detailed information on the types of mounts/rings/etc. you are attempting to use, how you are mounting them up, the optics in question, etc., etc.?

Out of curiosity, how does the rifle shoot with the iron sights?

Also, what twist barrel does it have and what ammo are you using?

Finally, any pics of the rifle/mounts/rings/scopes/etc. available? Might help to point out any issues...might not.

 

[john_m44]

Does it shoot with iron sights? I have a hard time seeing such a discrepency of an upper reciever. Have you tried at 25 yards?
Did you try a different round? If your twist is one in twelve and you tried using match rounds of 77 grains - there may be a problem.

I have not tried it with iron sights, Im not that good with them.
I have used burris signature rings with the offset inserts to get it on paper at 100 and after I did it shot really well. Around 1"

There are adjustable for windage bases, but I am having a hard time thinking you upper reciever is that crooked. I mean it could be, but then just changing your barrel isn't going to fix anything when it could be a problem with the upper. Maybe barrel nut interface with the upper reciever? So take the hanguards off and lay a straight edge down the reciever and barrel. If it is crroked, it will be noticable and you would then be off.

In order to use the Burris rings I have to use a scope riser. I would just soon not use the riser. Id like to be able to use the ADM mount and to the best of my
knowlage they are not windage adjustable.

Thanks for the suggestions

 

[john_m44]

ORD

It is a flattop with thumb screw removable carry handle.

I Have not shot it with Iron sights. But after I was able to get it on paper it shot rather well.
It is a 1:9 I cannot get it to group reloads between 40 and 69 grains, but with rem-umc 45g HP it will keep 5shots around 1".

As for pictures Ill get some tomorrow.

Thanks for the help

 

[ORD]

ORD

It is a flattop with thumb screw removable carry handle.

I Have not shot it with Iron sights. But after I was able to get it on paper it shot rather well.
It is a 1:9 I cannot get it to group reloads between 40 and 69 grains, but with rem-umc 45g HP it will keep 5shots around 1".

As for pictures Ill get some tomorrow.

Thanks for the help

Ok...flattop with the removable carry handle is the A3 Target model.

Also, you mentioned in your first post that you couldn't get enough windage adjustment to get on paper at 100yds, but above, you stated you did get on paper and it actually shot pretty well. How much windage did you actually consume getting the rifles on paper? If the scopes were new to you (used or NIB) when you went to mount them, you might try rezeroing them to mechanical zero for BOTH elevation and windage so that you are actually in the middle of each scope's adjustment ranges when you start zeroing to ensure you have max windage and elevation available to you from the get go.

What about the mounts/rings/etc. used to mount up your two scopes that you tried to get zeroed before running out of windage (and out of curiosity, which direction was it WAY off toward)? I saw above where you mentioned "burris rings" and a riser, but which specific Burris rings and what make/model riser? Did you properly torque the riser, rings (cross bolts and cap screws) down per whichever mfg made them? What about the scopes themselves (make, model, age, any probs on other rifles, etc.)?

I have seen problems with multiple cheap risers/mounts/ring/optics combos over the years leading to windage issues, but none so bad that the rifle simply couldn't be zeroed at all.

 

[john_m44]

ORD

I used Burris signature rings with the offset spacers. If I remeber right it took around 20 moa in the rings and about all of the windage in the scope to zero it. The riser is a el cheapo, but I acutally mounted it and seen it was off, so I turned it around and remounted it and it was still off in the same direction. So in my mind that checks out.

The first scope I tried was a Bushnell Legend 5-15x40 NIB, the second scope that I tried was a proven Simmons 44mag 6.5-20x44(I know not the best scope but It works fine for me.)

Im not new to mounting optics, just havent done many on AR rifles.

Im a little slow on typing so bear with me.

Thanks for your time

 

[rjacobs]

You say you are in Missouri. If you are in St. Louis I would be glad to take a gander at your rifle for you if you want to see if anything is grossly off. We could even pull your barrel and re-torque it and see what that does. Im guessing something is grossly out of spec to take 20 moa in the rings and probably another 40-50 moa in the scope to get zero'd. Sounds like the rail is WAY out of spec or the barrel isnt torque'd right. Something is up for it to be that far off.

 

[john_m44]

I have took the barrel off, cleaned the barrel ext. and retorqued it.

rjacobs Im alot closer to KC thanks for the offer.

 

[rjacobs]

I think something in your upper receiver is off, most likely the rail is not machined right. If it was doing this with the iron sights I would venture into canted FSB territory, but with a scope, the only thing you are indexing off of is the top rail on the receiver. So its either that or the portion of the receiver that your barrel screws into is off. You could get a new stripped upper receiver and transfer all of your stuff onto it for anywhere from 50-80 dollars however I am always hesitant to replace parts without knowing exactly what is causing the issue.

 

[ORD]

ORD

I used Burris signature rings with the offset spacers. If I remeber right it took around 20 moa in the rings and about all of the windage in the scope to zero it. The riser is a el cheapo, but I acutally mounted it and seen it was off, so I turned it around and remounted it and it was still off in the same direction. So in my mind that checks out.

The first scope I tried was a Bushnell Legend 5-15x40 NIB, the second scope that I tried was a proven Simmons 44mag 6.5-20x44(I know not the best scope but It works fine for me.)

Im not new to mounting optics, just havent done many on AR rifles.

Im a little slow on typing so bear with me.

Thanks for your time

If you have mounted the riser and know that it is "off" regardless of which direction its off, then your problem has to either lay: 1) with your upper receiver's picatinny rail that's integral to the receiver itself (not unheard of, but it'd be the first I've seen or heard from BM although their QC is somewhat lacking in my experience, but that's one hell of a bad thing if its the upper!); or 2) with your riser rail and/or its mounting hardware (probably more likely than the receiver itself being that far off and you yourself admitted its an "el cheapo" riser).

If its your upper receiver's rail, you can attempt to get some satisfaction from BM, although you are likely up up a creek in dealing with the monkeys there in my experience. If that is the source of the problem, you are fortunate that quality forged upper receivers that are well-known to be in spec can be had for pretty cheap (<$100). Like rjacobs said, its a relative quick fix as you'll just need to swap your existing upper's parts/hardware over to the new one and then proceed to use the old, @#$%ed up BM upper as a paperweight!

If its the riser, that's also a fairly cheap fix. There are quality AR risers available for ~$50 depending on the features you want/need, or, the better option would be to source a suitable one-piece mount with enough forward offset to get the scope's eyepiece where it needs to be for you to get a proper position on the rifle. You don't have to do QD with a $150+ ADM mount, etc. to get good quality.

Again, some pics when you have the time might help us in helping you get to the bottom of this issue.

Hang in there!

 

[john_m44]

I believe I have it figured out. Pictures and explanation to come. I have run out of time tonight.

 

[tipper]

More to come,tag for later

 

[john_m44]

I worked with it Sunday afternoon, first thing I did was remove the freefloat handgaurd and reinstall the factory handguard. The next thing I did was remove the el cheapo riser and installed a set of Burris high XTR rings and remount the scope.

I took it to my range and fired it 10 times, the windage problem was fixed, only thing I wasnt to happy with is it didnt group as good as it had before. But I can deal with that because my main goal is to install a 204 Ruger barrel.

 

[DBoz]

The looser groups could be due to removing the free float hand guard. Anything touching the barrel, such as the factory hand guards, can affect your grouping. I would put the free float guard back on (if possible ) and see if you get tighter groups with the new rings.

 

[ORD]

I worked with it Sunday afternoon, first thing I did was remove the freefloat handgaurd and reinstall the factory handguard. The next thing I did was remove the el cheapo riser and installed a set of Burris high XTR rings and remount the scope.

I took it to my range and fired it 10 times, the windage problem was fixed, only thing I wasnt to happy with is it didnt group as good as it had before. But I can deal with that because my main goal is to install a 204 Ruger barrel.

I highly doubt that the FF tube was in any manner responsible for your wild windage issues, but rather was solely due to the garbage riser causing your issues. As for your new accuracy/grouping woes...with having to mount your scope that far rearward and then having to contort yourself all around on the rifle instead of having the eyepiece up where it should be, etc., etc., those things in and of themselves are enough to open up your groups significantly, not to mention the lack of free-floating at that point in time.

Having resolved your windage woes and showing that your receiver isn't out of spec, you can at least proceed with your .204 Ruger project and once you've gotten your new barrel and other stuff in hand, you can source a proper mounting solution for it, whether its a quality riser/rings combo or a 1pc mount with some degree of forward offset to get your scope height and positioning of the scope fore/aft on the rifle correct for you.

 

[john_m44]

I highly doubt that the FF tube was in any manner responsible for your wild windage issues, but rather was solely due to the garbage riser causing your issues. As for your new accuracy/grouping woes...with having to mount your scope that far rearward and then having to contort yourself all around on the rifle instead of having the eyepiece up where it should be, etc., etc., those things in and of themselves are enough to open up your groups significantly, not to mention the lack of free-floating at that point in time.

Having resolved your windage woes and showing that your receiver isn't out of spec, you can at least proceed with your .204 Ruger project and once you've gotten your new barrel and other stuff in hand, you can source a proper mounting solution for it, whether its a quality riser/rings combo or a 1pc mount with some degree of forward offset to get your scope height and positioning of the scope fore/aft on the rifle correct for you.

Im going to reinstall the FF Tube, and retest. As for the burris XTR rings, that is all I had to work with here, I do have a Burris PEPR but no 30mm scope that isnt mounted.

Right now Im going to start with just a barrel swap, but in the future it will be a complete upper in 204 Ruger.

Thanks for the help everyone!!!!

 

[ORD]

Im going to reinstall the FF Tube, and retest. As for the burris XTR rings, that is all I had to work with here, I do have a Burris PEPR but no 30mm scope that isnt mounted.

Nothing wrong, per se, with the XTR rings, but the lack of forward offset makes standard rings on an AR-15 and a larger, magnified optic, more or less not a workable solution (at least beyond a quick and easy test to ensure your receiver's rail isn't out of whack). Once you get everything squared away, drop back in re: mount setups as there are a veritable $#!%TON of options for quality mounting solutions out there, including some good ones that won't break the bank and will serve you well in the long haul.

Congrats again on getting the ghost out of the machine and good luck with your .204 build.