Bedding AR10 / LR308 actions

[LongArm]

Re: Bedding AR10 / LR308 actions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NYresq</div><div class="ubbcode-body">you said you would reverse it next time, why put the marine tex in the lower instead of the upper lug??

And did you do anything on the front lug?

I see the lever system you hung it by the barrel to dry, but how did you apply downward pressure on the front lug? wouldn't hanging it by the barrel like that cause the front lug to push up and forward against the pin instead of pulling down?


I would think it would be better to have a straight up/down pull to apply pressure against the length of the mating faces on the upper and lower to be better. or does it not matter? </div></div>


I would put the bedding in the lower rear (under the rear lug area) as a way to better judge how much is needed. The upper would still be the only that the bedding would stick to. It is very hard to tell how much is enough by putting bedding on the lug itself. putting the bedding in the lower part it is easier to tell if you have enough. Again it will only stick to the upper. I did lightly bed the front lug. This was not for up or down play but for side to side play. Up or down pressure was not really a concern.

However after reading the last part of your post I agree with you on the equal down/down pressure. It is something I had not thought of! I don't know it the way I did it would matter but the way you are explaining it would seem to be a better method.

 

[Grump]

Re: Bedding AR10 / LR308 actions

I would still like a report of whether and how much it affected group size.

For many, the satisfaction of silencing the "rattle" will be more than enough payoff. But having personally seen an Accu-Wedge make no accuracy difference in both 5.56mm and a 6.5 Grendel, I always look for more anecdotes in the hope of someday acquiring enough to be "data".

 

[LongArm]

Re: Bedding AR10 / LR308 actions

I free floated the barrel and added a adjustable gas block. i took out the Tubbs carrier weight sys but kept the tubbs spring. I now shoots just over 1". The best group on the first loading I did was 1.061" exactly. I loaded 43, 43.5, 44, 44.5, 45, 45.5 grains of varget loaded a COAL 2.805" with 168 A-Max bullet. It shoots 147's like buck shot.

<span style="font-weight: bold">The squares are 1/2" outside to outside</span>

This was brass that was prepped and primed a long time ago. I could not remember if they were primed with magnum primers or reg fed primers. Some of the brass neck tension was greatly different when they were seated. The Trijicon Accupoint scope's triangle is not the greatest for squeezing out accuracy from a weapon due to the tip of the triangle not being like that of a cross hair.

So your mileage may vary. But reducing the amount of gas and free floating the barrel also helped. The loads were a step in the right direction. I can definitely live with 1"moa 5 round groups, since it started out as a sloppy 1.5"-2" group rifle. I know I can squeeze out more accuracy with better loads, but that will have to wait until a different scope arrives.

To recap, did the bedding help? I am not sure. Did it make anything worse? No it did not. There have not been any mysterious flakes in the trigger either. In fact I actually sent 2 rounds off early because I was not use to how light the SDE 3.5lbs trigger was. So there will be some accuracy gains by just shooting it more.

 

[kb1]

Re: Bedding AR10 / LR308 actions

Did you look at the idea of adding a tensioning screw? It's really not that difficult. All you really need is a drill press and a decent vise. I've done it to a few sloppy upper/lowers and it works quite well. I'd be afraid of gluing my upper and lower together.

 

[Possum]

Re: Bedding AR10 / LR308 actions

You wanted to get your lower to fit tight... Mission accomplished.
Good on ya for thinking outside the box.

That being said (I may have missed it in this thread) is the outcome any different/better than using the lil red wedge ( "the gapper" I think it is called)

 

[LongArm]

Re: Bedding AR10 / LR308 actions

I changed the scope from the trijicon pictured below to a Vortex PST 2.5-10X44. I think that this will also tighten up the groups due to it being a finer cross hair than the trijicon triangle.

I re-weighed it and loaded with scope/mount, a p-mag, 7 rounds and a large red game flash light it weighed 12lbs total.

Here is a mod I did to free float the rail around the Syrac adjustable gas block. It was super easy. As I say I went "full redneck" on it and dremel'd a small section of rail out. After that it was free floated. I think I did this after I shot the groups. I need to re-shoot the groups to see if it changed. I will say that it definitely likes the heavy bullets better i.e. 168's and up.

The more I shoot it the better I get. The trigger is awesome and light. Its a lot lighter than stock.

 

[SONIC SAAMI]

Re: Bedding AR10 / LR308 actions

This thread is full of WOW

 

[cvcustom]

Re: Bedding AR10 / LR308 actions

Thinking outside box awesome and giving people options love or hate his idea its still an option

 

[hrfunk]

Re: Bedding AR10 / LR308 actions

My department acquired a DPMS SASS a little over a year ago. My partner has been driving it since he went to Sniper training and it has been a good rifle. I'm not sure how many rounds he has put through it, but I would guess he's gaining on a thousand. He's had no malfunctions of any kind and his accuracy looks to run 1-1.25 MOA. It is my understanding that a few years ago, DPMS had problems with their magazines which caused malfunctions. they have since re-designed their mags. Based upon what I've seen, the problems appear to have been rectified.

HRF

 

[LongArm]

Re: Bedding AR10 / LR308 actions

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">This thread is full of WOW</div></div> Thanks

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Thinking outside box awesome and giving people options love or hate his idea its still an option</div></div>
I always wanted to know more about bedding the actions. I think for long range stuff (800yrds +)it would help. I had the stuff to do it so I did.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">My department acquired a DPMS SASS a little over a year ago. My partner has been driving it since he went to Sniper training and it has been a good rifle. I'm not sure how many rounds he has put through it, but I would guess he's gaining on a thousand. He's had no malfunctions of any kind and his accuracy looks to run 1-1.25 MOA. It is my understanding that a few years ago, DPMS had problems with their magazines which caused malfunctions. they have since re-designed their mags. Based upon what I've seen, the problems appear to have been rectified.</div></div>
I primarily use the P-Mags but the metal DPMS mag have worked great as well! The only issue with this rifle is that it was severely over gassed. It still functioned and ran, but it would have greatly shortened the life of the bolt and springs had it not been addressed.

 

[Ledzep]

Re: Bedding AR10 / LR308 actions

I did something similar once.

I put release agent on EVERYTHING. Then pour the epoxy into the lower, plop on the upper and let it set up.

Then when you knock the two apart, pop the epoxy out and shape it so it easily goes in and out. That "wedge" is now a perfect fit for that specific upper.

I did not notice a difference in accuracy, So I gave up on it. I may try it again, though, now that I have a Krieger barrel on my new .260.

Edit to add: Might give this a look. http://www.midwayusa.com/product/344332/...0-and-sr-25-281

 

[LongArm]

Re: Bedding AR10 / LR308 actions

I think if one were going to shoot out past 700 yards there might be an accuracy increase. This being due to the extreme range and lack of upper shift/wobble during bullet travel in the barrel????

I agree on the "pour the epoxy into the lower" part. It is easier to tell how much you need when it is done that way.

 

[ArmyJerry]

good thread

 

[Regalkismet]

WOW.... Just wow.

 

[msat10]

I took the easy way out, just bought a LWRC REPR and never looked back....

If you have the time and skill to bed the action, go for it...

 

[M25BeastShooter]

Not sure if reading through the thread if any major improvement came out of this project or any new techniques were discovered but I can tell you that back in 1990-1991 when I was down in Ft Benning and shooting with the AMU the armorers there were going nuts trying to get the M16A2's to be "tight" like the M14's. Smitty (one of the old timers) told me that they tried to bed the rifles, weld plates in the receivers, even building up the metal to make the rifles tighter. None of it ever worked. They found that the following improvements were all they needed to make the rifles shoot sub-moa:

Good Barrels
Free Float handguards
Great triggers
Later pinned rear sight posts
Good quality heavy bullets 77's 200-300 80-90 gr for 600-1000

 

[LongArm]

I agree on the above statements. With that being said, I'd do it again. I think that it helps and the groups are now easy sub moa (after a barrel change to rainiers select match).

 

[Snuby642]

I didn't see anyone state the ovius!
Get an upper and lower frome the same manufacturer, they will fit better!
There's a certain amount of necessary play between AR parts, ie for when they heat up.

As a permanent fix for the problem take it to a weld shop and have the upper and lower heliarked together!


won't rattle and would never have to listen to you rattle iether. LOL

 

[Itsadryheat]

this is interesting, I have always thought that having a free floating hand guard was what was needed for an AR10/AR15 platform.... I have bedded my m1a rifles and bolt rifles but never an AR..

 

[Cavitation]

A piece of rubber even cardboard or an accuwedge will tighten everything up just fine.
No need to over due it...but hey new experimental results good or bad are information we can all use.