Gunsmithing Lost accuracy - Opinions wanted

[vman]

Hi Guys.

Recently my rifle has not been performing well. It used to shoot very well, and for a factory barrel I could not complain. However recently its shooting more like a cheaply made rifle with around 1.5 MOA at 100 yards.

At first I did not really notice as I rarely shoot at 100 yards, but I was putting the mid range, poor accuracy down to the possibility of wind or just having a "bad day".

Yesterday I put a target out to 400 yards. I confirmed a few shots at a gong and then decided to move on to paper. Suprisingly a few shots at the gong missed which is very odd. I then moved on to the paper, at which the accuracy was very poor.

I had tested out a Roedale clamp on muzzle brake a little while ago and Im wondering if perhaps it has left a tight spot in the muzzle? I was pre-warned of this by my smith a while back, however the opportunity presented itself to try out this product and I went ahead.

Rifle in question is a 700P in .308 26" barrel 1:12 twist with about 1500 rounds down the tube.

The barrel has had a good clean, and all action screws torqued properly. Everything sits in an AICS, which has adequate barrel clearance.

What would you do?

A) Rebarrel, which is the most expensive option
B) Have the barrel shortened, however there is less certainty this will solve the problem.

Or perhaps there are other suggestions?

 

[former naval person]

Re: Lost accuracy - Opinions wanted

All the usual stuff first. Loose mounts, chipped bedding (if bedded), dying scope, old ammo (sometimes varying neck tension with ageing/brass hardening), contaminated ammo...let someone else shoot it to eliminate operator error. If all is okay there, then address the barrel issue...soft lead slug from chamber end to muzzle. (Clean the barrel thoroughly and lightly oil. Insert slightly undersized lead slug into the bore at the chamber. Back it up with a 1/4 diameter brass rod and drop a longer brass rod in from the muzzle. Drop it a few more times to expand the slug into the rifling. Push it slowly through the barrel. You'll be able to ascertain if there is a tight spot close or at the muzzle.) That should get you the answer you seek. JMHO

 

[SScott]

Re: Lost accuracy - Opinions wanted

Take the action out of the stock, look it over real well, put it back in ensuring that there is no binding anywhere and that the recoil lug is coming against the stop while the action screws are free.
Mount a different scope, checking the base and rings while you are at it.
Try a known "good" ammo, wether it be factory or, a tried and true hand load.
Good luck, and please share with us when you find the problem, as it is pretty rare for a .308 to shit the bed with that many rounds down the tube.
SScott

 

[chpprguy]

Re: Lost accuracy - Opinions wanted

Did you check your crown?

 

[Tripwire]

Re: Lost accuracy - Opinions wanted

Rate the accuracy prior to the brake, while using the brake, and after it was taken off.

This could point you in the obvious direction......

 

[ArcticLight]

Re: Lost accuracy - Opinions wanted

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">Hi Guys.

Recently my rifle has not been performing well.
Rifle in question is a 700P in .308 26" barrel 1:12 twist with about 1500 rounds down the tube.

The barrel has had a good clean,

What would you do?


Or perhaps there are other suggestions? </div></div>

C) Put 35 rounds through it, use factory cheap ammo.


And don't clean it like that anymore!

My factory tube does NOT like to be cleaned all that often.

When I do clean it, it's 1 wet patch, 1 more wet pathc - wait 5-10 mins and 3-5 dry patches.

Tha'ts it, other than Q-tipping the bolt face and cleaning the chamber occasionally.

I use Militec-1 on the bolt.

 

[vman]

Re: Lost accuracy - Opinions wanted

The AICS has a V Block.

Pre muzzle brake, the rifle would shoot 0.3 to 0.5 MOA out to 400 yards.

I rarely ever cleaned the barrel. I have always been on the train of thought that when accuracy starts to go, then give her a good clean.

A Mike Lucas bore guide has always been used when a clean did occur, so im certain theres no added throat damage from cleaning.

The ammo has been handloads, either Lapua Scenars or SMK's, in lapua brass, behind varget.

Scope is a Nightforce.

I will investigate more and see what I can come up with.

 

[Country]

Re: Lost accuracy - Opinions wanted

When accuracy suddenly goes off always suspect the scope first.
However I would also suspect neck hardening of the brass and barrel fouling from the sound of your posts. You may not have done a good job cleaning at times . The fouling could have just slowly built up to a point that it is causing trouble add that to hardening case necks .
1500 rounds should not shoot out a new 308 W barrel.
It's worth a check just to rule it out as a possible cause.
I don't believe any clamp on muzzel brake could crush the barrel .

 

[cvedrick]

Re: Lost accuracy - Opinions wanted

You might be getting copper fouling or a carbon buildup near the throat. Do you have or know someone with a borescope? might just be worth looking at...

 

[customshooter]

Re: Lost accuracy - Opinions wanted

try sweets....

 

[PBRACEGUNS]

Re: Lost accuracy - Opinions wanted

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cvedrick</div><div class="ubbcode-body">You might be getting copper fouling or a carbon buildup near the throat. Do you have or know someone with a borescope? might just be worth looking at... </div></div>

This theory gets my vote too. I had a Savage that seemed to suddenly lose accuracy at only 800 or so. Put the borescope in after I <span style="font-style: italic">thought</span> it was Cleaned well. Found very long streaks of copper in the throat area and within 2 " of the muzzle.
JB bore paste on the Felt pellet bobs with a little Kroil and some 80 - 100 passes through the bore then 1 Sweet's soaked patch. Waited a few minutes and dry patched till they came out clean. Rifle went back to the pre- fouled accuracy.
Just my .02

 

[Hummer]

Re: Lost accuracy - Opinions wanted

I have seen Rem 700 barrels go out in 500 -1100 rounds. I know a gunsmith who has seen similar in five different rifles.

You might could set the barrel back a full set of threads and bring it in. Also whack about 1/4" to 1/2" off muzzle and recrown.

If you get access to good borescope look closely at condition of barrel just inside muzzle. Hammer forged barrels have a bad habit of starting to flake out (for lack of a better term) pieces of metal at the muzzle. I have had I guess three hammer forged barrels to do this.

A good tool to check this is the muzzle gage from the Civilian Marksmanship Proram here in the states.

Frequent cleaning while barrel is still hot will do great things in keeping the carbon from getting hard when it cools down which just embeds in copper bullet jacket and goes down bore cutting and whacking .

I ran a test on a new Remmy barrel about 8 years ago and I cleaned it warm every 12 rounds or so. Normally on a new barrel the reamer marks (in the throat) are gone between 100 and 150 rounds.

With the enhanced cleaning schedule I still had reamer marks at 800 rounds and a a couple of sessions got the barrel very hot and I got enhanced readings of erosion gage in 30 rounds of shooting.

In my testing I started off with 30 rounds in 30 minutes and barrel got to 122F. Working from memory here and assuming I am remembering correctly a round every 30 seconds took barrel temp to 165F and a round every 15 seconds took it to 195. On both those 30 round runs I got a big change in erosion gage.

These were done around the 600 round point.

I pulled the barrel at 900 rounds as I had found out what I wanted to know. To look at it, it looks perfect but a borescope tells the tale.

 

[The Shottist]

Re: Lost accuracy - Opinions wanted

So your testing implies that Remington is using a lower grade of steel, one that deteriorates more quickly than the premium barrels sold by the premium barrel makers.

 

[sinister]

Re: Lost accuracy - Opinions wanted

If the rifle was stock, with original factory barrel, you may have reached the point where the 700's long factory throat is now providing enough free-bore jump to affect your groups.

What bullet weights are you using, and if you've mic'ed your throat how far are your bullets jumping?

 

[DHDeal]

Re: Lost accuracy - Opinions wanted

My shooting partner bought a Hawkeye because he felt we really did not know what was going on inside the barrel. What we thought was clean (patches without blue/black after cleaning) was not. We had some monumental carbon build up from the throat + 8" or so.

FWIW, I shoot mainly a Gradous built Surgeon actioned 308 and my partner shoots a BAT actioned 6mmBR. Both have Krieger barrels and both rifles shoot very well. You know when something ain't right, quick fast and in a hurry!

Neither one of us had ever done more than used brushes/patches on the barrels. That damn borescope told the tale. After spending some quality time getting rid of the carbon, my 308 immediately shot like it was new again.

The point I am getting to is you really have no idea how clean, or not, your barrel is without a borescope. That having been said, knowing what I know now, I ain't afraid of either Iosso or JB's anymore. Between us we have about all the available bore solvents/copper cleaners. Nothing touched the carbon that we could tell besides Iosso and JB's.

Also, copper is a piece of cake to remove, carbon is the real problem I believe.

 

[Shooterken]

Re: Lost accuracy - Opinions wanted

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DHD</div><div class="ubbcode-body">My shooting partner bought a Hawkeye because he felt we really did not know what was going on inside the barrel. What we thought was clean (patches without blue/black after cleaning) was not. We had some monumental carbon build up from the throat + 8" or so.

FWIW, I shoot mainly a Gradous built Surgeon actioned 308 and my partner shoots a BAT actioned 6mmBR. Both have Krieger barrels and both rifles shoot very well. You know when something ain't right, quick fast and in a hurry!

Neither one of us had ever done more than used brushes/patches on the barrels. That damn borescope told the tale. After spending some quality time getting rid of the carbon, my 308 immediately shot like it was new again.

The point I am getting to is you really have no idea how clean, or not, your barrel is without a borescope. That having been said, knowing what I know now, I ain't afraid of either Iosso or JB's anymore. Between us we have about all the available bore solvents/copper cleaners. Nothing touched the carbon that we could tell besides Iosso and JB's.

Also, copper is a piece of cake to remove, carbon is the real problem I believe. </div></div>

So how often do you suggest cleaning the barrel?

 

[customshooter]

Re: Lost accuracy - Opinions wanted

final attempt - use JB bore cleaner and then the polish.....

 

[cappaletti]

Re: Lost accuracy - Opinions wanted

gotta go with customshooter...JB compound is excellent stuff, however, FOLLOOW THE DIRECTIONS printed on the container. It should require no more than 8-10 passes with the bore cleaning compound. It's abrasive and too much scrubbing can really mess up the inside of ur bbl. If ur rifle isn't bedded u mite consider doing that with free floating of the bbl IMHO ! Good luck !!!