LVLAaron
Gold $$ Contributor
That's interesting. I guess I could load from the mag and then remove it and single fire to see if that's happening.
Trouble with a newly build 308 AR10
- Thread starter LVLAaron
- Start date
That's interesting. I guess I could load from the mag and then remove it and single fire to see if that's happening.
I have a 20" Mega Maten 308 that I built a couple of years ago.
After break-in with cheap ZQI 147gr NATO, I used 168gr FGMM to test accuracy with factory ammo. It gave me underwhelming accuracy like you're seeing.
I switched to 175gr FGMM and the groups tightened up to under an inch...my barrel likes heavier bullets. 175 SMK's and 178 A-Max's shoot less than 1/2" groups with 42gr of IMR4064.
Try heavier bullets and see if that helps.
The suggestions for an adjustable gas block are good, but I don't think that's the problem. The reduced bolt carrier speed will reduce recoil, wear and tear and make brass easier to find.
I have the SLR Sentry 7 SS clamp-on. It works great...recoil is not much more than my 223/556 AR's.
After break-in with cheap ZQI 147gr NATO, I used 168gr FGMM to test accuracy with factory ammo. It gave me underwhelming accuracy like you're seeing.
I switched to 175gr FGMM and the groups tightened up to under an inch...my barrel likes heavier bullets. 175 SMK's and 178 A-Max's shoot less than 1/2" groups with 42gr of IMR4064.
Try heavier bullets and see if that helps.
The suggestions for an adjustable gas block are good, but I don't think that's the problem. The reduced bolt carrier speed will reduce recoil, wear and tear and make brass easier to find.
I have the SLR Sentry 7 SS clamp-on. It works great...recoil is not much more than my 223/556 AR's.
This is a good place to look... Tighten and loosen back and forth till you get what you want.. to much torque on the barrel and you will have problems...
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I had an AR15 that wasn’t shooting too great, 1.5”+ groups. I sanded down the lower receiver at two points over each takedown pin and bedded it with DevCon. I also adjust my gas block so that the gas tube passed through the upper receiver with almost no contact, where before it rubbed on one side with a little pressure. Groups were cut in half(and the rattle went away). The gas tube is definitely worth looking at, I only did the bedding because it is a cheap lower and I didn’t mind some imperfections in finish. Wouldn’t recommend to everyone.
LVLAaron
Gold $$ Contributor
Those are some good ideas I'm going to look at on all of my AR's! - I'd never considered bedding an AR but some quick searching makes it look like a pretty normal procedure. I use Aero receivers and they have an adjustment screw under next to the grip screw threads that rises up into the upper to keep things tight so I never thought much about it after that.
When I tear this guy down I'l clean the gas tube and bolt carrier and get some dye chem on the tube, cycle it a bunch and see how/where it's rubbing.
Good ideas!
My brother has the aero lower with the set screw, and it tightens up the fit, but just like you wouldn’t want a single high point in the bedding of a bolt gun, I don’t find it to be great for accuracy.
and bed that barrel extension into the reciever with locktite
Just my opinion here.. That proper staking be used but if you must add locktight use proper staking and purple locktight so that it may be removed without heat.... I have also found that some play between the upper and lower doesn't affect accuracy that much since the BCG , barrel , receiver ext. and optic are all part of the upper...
But I have seen over torqued barrels be extremely bad with accuracy...
But I have seen over torqued barrels be extremely bad with accuracy...
you don't use locktite on the barrel nut. what you use it for is to fill the space between the barrel extension and the reciever. bedding to reduce the movement of the barrel in the reciever. it has worked for me. took an inconsistent 3/4 to 1" gun to a very consistent 1/2 to 5/8" gun. Read about it.
not the face. i do lap the face of the reciever. that has also made accuracy improvements.
you spread locktite on the entire barrel extension where it fits into the reciever. this fills the space between the barrel extension and the wall of the reciever. now if your reciever extension is so tight you have to drive it in with a rubber mallet it won't help much but if your barrel extension slips in then you know you have space around it. if you don't do this then the only thing keeping the barrel from moving is where the face of the reciever and the face of the barrel extension mate. just a little wiggle will make a huge difference in accuracy.
now i wouldn't do this to a SHTF gun but if you are going.for.accuracy my experience is it helps. Pretty common practice in accuracy builds.
i use red locktite and i have changed out barrels afterwards. don't worry they will come back apart. just don't get it on the barrel nut.
LVLAaron
Gold $$ Contributor
Seems that Pacific Tool is taking ages to get their lapping tool out the door to me so I put on the Faxon barrel today.
First thing I noticed was the faxon was perfectly snug in the upper receiver / and the Ballistic Advantage I've been using had all sorts of slop. New barrel, new adjustable gas block.
Will load up some junk to break in the barrel and then fire some boxes of Federal Gold Match through it to see what I can do.
It's about 15 degrees here so I'll need to order some bigger balls and go shooting in the next couple of days.
First thing I noticed was the faxon was perfectly snug in the upper receiver / and the Ballistic Advantage I've been using had all sorts of slop. New barrel, new adjustable gas block.
Will load up some junk to break in the barrel and then fire some boxes of Federal Gold Match through it to see what I can do.
It's about 15 degrees here so I'll need to order some bigger balls and go shooting in the next couple of days.
Seems that Pacific Tool is taking ages to get their lapping tool out the door to me so I put on the Faxon barrel today.
First thing I noticed was the faxon was perfectly snug in the upper receiver / and the Ballistic Advantage I've been using had all sorts of slop. New barrel, new adjustable gas block.
Will load up some junk to break in the barrel and then fire some boxes of Federal Gold Match through it to see what I can do.
It's about 15 degrees here so I'll need to order some bigger balls and go shooting in the next couple of days.
Yeah, 15 is a little cold...
I've heard of some to wrap the barrel extension in a shim to reduce the slop; also AR15 trick applied to the 308 of "bedding" the extension into the upper with loctite works great. I'd recommend purple 222 or blue 242 for easier disassembly vs. the red. Barrel nut to 30 ft-lbs plus next aligned gas tube hole or notch. I use a flashlight in the receiver to make that part easy. Then install BCG before gas tube and gas block aligning such that there is no contact on barrel nut or receiver.
A JP vise block set makes this easy; but holding entire assembly upside down on a table works too.
-Mac
the wheeler gas tube alignment tool makes checking for a clear path for the gas tube through the barrel nut very easy. if the rod on the tool passes through the the gas tube path is clear. very important that the gas tube is not in contact with anything.
i have found that the reciever facing tool helps in that respect too! when you have the barrel nut torqued to perfection and the nut splits the hole just a little, and i mean a little, facing and everthing lines up perfectly. i like it better than shims.
6MMsteve
Gold $$ Contributor
why is that sawstop in the corner no dust what do you mean, nice gunSeems that Pacific Tool is taking ages to get their lapping tool out the door to me so I put on the Faxon barrel today.
First thing I noticed was the faxon was perfectly snug in the upper receiver / and the Ballistic Advantage I've been using had all sorts of slop. New barrel, new adjustable gas block.
Will load up some junk to break in the barrel and then fire some boxes of Federal Gold Match through it to see what I can do.
It's about 15 degrees here so I'll need to order some bigger balls and go shooting in the next couple of days.
I used it to whip up that receiver jig in a few posts up.Nice to know I will look it up.. and ohh god don't use locktight on the barrel nut..lol
Sorry I see it says barrel extension , for some reason I thought I read receiver extension or some call it a buffer tube either way is correct to me.. I see what your saying and I will have to do some reading on it.. I am planning on building a full length gun soon may come in handy..
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