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Seriously! Nobody had an opinion!

Sniper1*

Lieutenant
Full Member
Minuteman
Nov 29, 2006
530
29
Rochester, IN
I have been shooting my RRA4 Varmint for about a year and a half. It shoots pretty well when I do my part, however, I have noticed that it shoots much better when using a bag instead of a bipod. I know this has to do with me and the forces I put on the rifle.

I have taken my Boresighter and put it in the gun and then got into shooting position. When doing this I can see the reticle move in the grid depending on the pressure I am putting on the gun. Obviously I can really crank on it but, I was a little surprised about the slight amount of pressure that would cause it to move.

It should be noted that this gun has the factory FF Aluminum handguard. The receiver has been trued and reassembled correctly.

As stated above, from a bag exerting minimal pressure it is easily sub MOA, but from a bipod it becomes erratic.

I was wondering about the PRI tubes, or any of the others that would make for a more solid lock up between the FF tube and the Upper Receiver!?

Any thoughts from the ones that know?

Thanks
 
Re: Seriously! Nobody had an opinion!

For precision a free float tube is typically necessary. I think you are on the right track with going FF. What kind of movement are you getting, in inches when bipod is used? Any free float tube such as PRI or YHM will do what you need.
 
Re: Seriously! Nobody had an opinion!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sniper1*</div><div class="ubbcode-body">I have been shooting my RRA4 Varmint for about a year and a half. It shoots pretty well when I do my part, however, I have noticed that it shoots much better when using a bag instead of a bipod. <span style="color: #FF0000">I know this has to do with me and the forces I put on the rifle. </span>
<span style="color: #3366FF">You just answered your own question.
wink.gif
</span>

I have taken my Boresighter and put it in the gun and then got into shooting position. <span style="color: #FF0000">When doing this I can see the reticle move in the grid depending on the pressure I am putting on the gun. </span> Obviously I can really crank on it but, I was a little surprised about the slight amount of pressure that would cause it to move. <span style="color: #3366FF">The reticle might be moving because there might be parallax present.</span>

It should be noted that this gun has the factory FF Aluminum handguard. The receiver has been trued and reassembled correctly.

As stated above, from a bag exerting minimal pressure it is easily sub MOA, <span style="color: #FF0000">but from a bipod it becomes erratic.</span>

<span style="color: #3366FF">By "erratic" you mean that groups open up from sub MOA to MOA? From sub MOA to 2 MOA? If it's the first then you need to shoot more off the bipod, if its the latter then your bipod might be loose on the bipod stud.</span>

I was wondering about the PRI tubes, or any of the others that would make for a <span style="color: #FF0000">more solid lock up between the FF tube and the Upper Receiver!?</span>

<span style="color: #3366FF">IMO, I don't think the handguard is the problem. BUT, as far as solid lock up is concerned larue and daniel defense have probably the most solid locking system among a few others.</span>

Any thoughts from the ones that know?

Thanks </div></div>
 
Re: Seriously! Nobody had an opinion!

Are you leaning into, and loading the bipod some when you shoot?
 
Re: Seriously! Nobody had an opinion!

NinjaP -

I do have a FF tube! The problems seems to be in the flex between the barrel nut and upper receiver.

Pupdawg -

I know I can exert pressure on the rifle to make an impact change and inconsistency. I am looking for a way to minimize this.

I am using a USO with Tpal and adjust for parallax! That is not the issue!

By erratic, I mean it goes from Sub MOA to +MOA with POA/POI change depending on the pressures on the rifle. The Bipod in on an ARMS throw lever mounted to a rail. Nothing is loose!

Not to toot my own horn, but I do know how to shoot! I am just looking for opinions on a better system to tighten up the flex that appears to be inherent to this particular system.

Steelcomp -

I can not load the bipod, it completely F***s up my POA/POI and group size. Again, it seems to go back to the FLEX in the barrel nut area of this system.

Anyone have any thoughts on PRI w/ Recce Rail or full length rail, Vltor CASV, or ARMS SIR.

I am figuring that by design these systems bridge the gap between the forearm/barrel nut/upper receiver giving the system a more solid platform.

Thanks for the responses!
 
Re: Seriously! Nobody had an opinion!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sniper1*</div><div class="ubbcode-body">It should be noted that this gun has the factory FF Aluminum handguard. The receiver has been trued and reassembled correctly. </div></div>

I would check here first to make sure the tube is contacting the the barrel extension and that you are getting proper torque on the barrel nut.
 
Re: Seriously! Nobody had an opinion!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sniper1*</div><div class="ubbcode-body">

I do have a FF tube! The problems seems to be in the flex between the barrel nut and Again, it seems to go back to the FLEX in the barrel nut area of this system.

</div></div>
S1 You said you trued the upper receiver. Was there a lot of play between the barrel and the upper? If there is you might want to bed the barrel to the upper with blue Loctite. Make sure your barrel nut is seated and torqued correctly and there is no play in the FF tube. I would be more inclined to believe that the difference lies in the way the rifle moves under recoil in the 2 different rest systems. Remember the rifle has already started moving before the bullet has exited the muzzle.
 
Re: Seriously! Nobody had an opinion!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rasp65</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sniper1*</div><div class="ubbcode-body">

I do have a FF tube! The problems seems to be in the flex between the barrel nut and Again, it seems to go back to the FLEX in the barrel nut area of this system.

</div></div>
S1 You said you trued the upper receiver. Was there a lot of play between the barrel and the upper? If there is you might want to bed the barrel to the upper with blue Loctite. Make sure your barrel nut is seated and torqued correctly and there is no play in the FF tube. I would be more inclined to believe that the difference lies in the way the rifle moves under recoil in the 2 different rest systems. Remember the rifle has already started moving before the bullet has exited the muzzle. </div></div>



+1 Assuming correct installation.....which may be a wrong conclusion, but if its been assembled correctly, there shouldn't really be any pressure on the barrrel nut that is causing poi changes.

Most likely problems for me with AR's:
1. recoil management including preloading and especially follow through. If how you load the bi-pod changes your follow through....there you go. Gas guns are much trickier for me to shoot well because they are so sensitive to recoil managment and follow through

2. Ammo: Good black hills factory ammo 77 and 75grain match will give me groups right around MOA. On a good day, I get sub moa. On a bad one, I get about 1.25-1.5. That variation is enough to look like i have a problem but I know its just me
blush.gif
 
Re: Seriously! Nobody had an opinion!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sniper1*</div><div class="ubbcode-body">NinjaP -

I do have a FF tube! The problems seems to be in the <span style="color: #FF0000">flex between the barrel nut and upper receiver.</span>

<span style="color: #3366FF">I still doubt that this is the problem. What makes you think that the there is movement or flex when using the bipod is beyond me. If thats the case, try and put bipod as close as you can to the barrel nut and shoot it like that. I'd bet you'll still get your erratic groups. Some shooters just do better off of a front and rear bag than a bipod for AR's.</span>

Pupdawg -

I know I can exert pressure on the rifle to make an impact change and inconsistency. I am looking for a way to minimize this.

I am using a USO with Tpal and adjust for parallax! That is not the issue!

By erratic, I mean it goes from Sub MOA to +MOA with POA/POI change depending on the pressures on the rifle. The Bipod in on an ARMS throw lever mounted to a rail. Nothing is loose!

<span style="color: #FF0000">Not to toot my own horn, but I do know how to shoot! I am just looking for opinions on a better system to tighten up the flex that appears to be inherent to this particular system.</span>

<span style="color: #3366FF">So it's not you causing the erratic shots? Its the "system"? Put another shooter on the rifle with the same loads and have him shoot off the bipod. If he can get better consistency out of it than what you can, ask him how he's holding the rifle. The AR platform WILL show you how inconsistent YOU are.</span>

Steelcomp -

<span style="color: #FF0000">I can not load the bipod, it completely F***s up my POA/POI and group size. Again, it seems to go back to the FLEX in the barrel nut area of this system.</span>

<span style="color: #3366FF">There it is again... the answer to the question. You keep saying that you can't shoot off the bipod (not loading the bipod means not being able to shoot off of the bipod) because it messes up your POA/POI. Try this the next time you shoot... Off of the bipod, get in the prone position and put your cheek FIRMLY on the stock as to "hold" it super tight/ down. Do a 5 shot group and rest, then try it again.</span>

Anyone have any thoughts on PRI w/ Recce Rail or full length rail, Vltor CASV, or ARMS SIR.

<span style="color: #CC0000">I am figuring that by design these systems bridge the gap between the forearm/barrel nut/upper receiver giving the system a more solid platform.</span>

<span style="color: #3366FF">They tie the upper receiver to the handguard and give you a continuous top rail. A Larue or daniel defense rail won't "flex" either, has a solid lock up, but doesn't provide a continuous top rail.</span>

Thanks for the responses! </div></div>
 
Re: Seriously! Nobody had an opinion!

Most of what I am talking about is easily observed with the "bore sighting" device in place and then getting behind the rifle in a shooting position. Depending on the amount of pressure and where I exert the pressure (cheek or grip) makes the reticle move substantially in the "grid" of the "bore sighting" device.

I understand if I was really horsing the rifle but my point is that it does not take much to move the reticle in the grid!
 
Re: Seriously! Nobody had an opinion!

I do understand what you're saying. But really, the boresighter on the end of the barrel doesn't necessarily mean anything. So the reticle moves when you exert different amounts of pressure...why or what this means, I have no idea.

I do know that what you've found to be true regarding the rifle not taking much to change POI/POA is exactly what I said earlier about being consistent. The level of consistency or inconsistency is more pronounced when shooting an AR platform than a bolt gun.

I just want to try and help. I would be very curious to the outcome of what I asked you to do the next time you go shooting. (about putting another shooter on the rifle with the bipod... tell him its a "challenge" to see if he can do better than you. hehe)
 
Re: Seriously! Nobody had an opinion!

Pupdawg - certainly do appreciate your input and will do exactly that. I will ask both of the other shooters on the team to take a turn and see what happens.

What this (Bore sighting device/Grid Movement) means is that where the barrel is pointed the bullet will go, which depending on the pressure may not be the same POA the scope it sighted at.

On the last trip I did move the bipod to the rear of the rail and it shot pretty well but being that it was only one outing I didn't want to get to excited about it. I will continue to try to maintain my consistency as it will only make be a better shooter.

I still think a "bridge" of sorts will make this a much stronger system and less prone to this issue.

I am not at all opposed to working at being a better shooter, but I am just trying to put together the most "bulletproof" system to help alleviate as many shooter errors as possible.

I am lucky in the sense that the Dept. buys my training ammo but it is definitely not an unlimited budget or time.

If I can make my argument to spend for a new forearm system to make the rifle a better/more consistent weapon I will fight for it. Is there any reason to not use PRI with a rail of some sort.

Oh Yeah! Someone asked earlier how far out of square the receiver was - I believe the smith said it was .004" out of square - which to him was a substantial amount. He is a very reputable and talented local smith that can build/fix guns on a remarkable level. I have no reservations that this gun is assembled correctly!

Again, anyone with any experience with the PRI or other that would "bridge the gap"?