[JohnD.]

I have a very accurate .223 that would average a 5 shot group at 100 yard at about 1/3". Took it prairie dog hunting a couple of years ago and after I got back, went to the range and about all I can get is 3/4" with same exact load. I've tried grouping this gun several times over the last couple of years with the same result. I did'nt run any more than 40-50 rounds between cleaning and I never let the barrel get real hot. I have checked the bullets relationship with the lands and it has not changed during this time. I even loaded some fresh rounds in Lapua brass that I hold back for accuracy purposes and still only get about 3/4". Now I'm thinking that the barrel just lost it's edge so on a whim, I loaded some 40 gr. bullets with same powder that I normally use and sent 5 down range and was astonished that 4 went through the exact same hole and one just touching. Thinking a fluke, I loaded 5 more and shot them and while it was'nt quite as good, it was as around 1/3". I have repeated this a couple more times. Sorry for being so long winded but I have been meaning to post this for along time as it has been bugging me. Sooooo, what happen to my original load? Thanks, John D.

 

[Gary in NH]

Before you discredit your ammo or gun, check the scope. Could be a lose optic, not completely rock solid in the mounts(check the mounts to see if they are loose), or a particular magnification where the scope doesn't track correctly (happened this past deer season to me, scope was dead on a 3x but when moved to 9x it hit way low and to the left).

 

[pauls]

Or it could be the bullet diameter........

unless the bullets you're seating are out of the same box as your PD load, the wear on the manufacturers bullet swaging dies might have changed minutely, but enough to cause a difference in your acuracy. Plausible especially since your 40 grain load is shooting so well.

 

[keithcandler]

Possible simple answer........

after a dog hunt, the leade grows. If you do not seat the bullet out further to "chase" the lands, then the group sometimes opens up. Often when a barrel gets worn, it may take the addition of 0.5g to your load.

No worries!

 

[Greyfox]

For a small change like that, the first place I'd look at is the crown. It's very possible that you dinged the crown somewhere during that hunt and it's an inexpensive problem to fix, definitely won't hurnt to do it anyway.

Rick

 

[Catfish]

I hear you say you clean your gun, but do you use copper solvent? If not it could be that. I talk to alot of guy that didn`t know you had to use a special solvent for copper. Second thought is setting out bullets to match throught errosion.

 

[Paul Workman]

I 2nd what Greyfox said...

I Took it prairie dog hunting a couple of years ago and after I got back, went to the range and about all I can get is 3/4" with same exact load.

I did'nt run any more than 40-50 rounds between cleaning and I never let the barrel get real hot. I have checked the bullets relationship with the lands and it has not changed during this time. I even loaded some fresh rounds in Lapua brass that I hold back for accuracy purposes and still only get about 3/4". Now I'm thinking that the barrel just lost it's edge so on a whim, I loaded some 40 gr. bullets with same powder that I normally use and sent 5 down range and was astonished that 4 went through the exact same hole and one just touching. Thinking a fluke, I loaded 5 more and shot them and while it was'nt quite as good, it was as around 1/3". I have repeated this a couple more times. Sorry for being so long winded but I have been meaning to post this for along time as it has been bugging me. Sooooo, what happen to my original load? Thanks, John D.

The PD trip and cleaning comes to my mind as well. If you take an eye loupe and look very closely at the transition between the bore and the crown, if you see ANY brush scratches, or the junction is the least bit "rounded", then giving the crown a touch-up might be all that is needed to get the accuracy back.

Have a look. I had the same problem with my 220 Swift. All it had were some hairline scratches from the bore brush. I bought a drill mounted crown lap from Brownell's and some 600 grit lapping compound, and in 15 minutes and very little fussing, and it was back to shooting one-holers. It went from 3/4" to shooting a 5-shot, 5 group agg of .287, and two of them were in the teens. Needless to say I was a happy camper. I've used the lap on several rifles now, and ALL of them responded positively where there was obvious damage/wear at the bore/crown junction.

The bore in the picture was just lapped. Notice the glint from the freshly cut ring junction between the bore and the crown, left by the lap. The rifle is Ami's new Salvage 12BVSS in .223. I lapped the crown b/c the new barrel had a rolled bur of metal all around the circumferance of the bore/crown junction. I never fired a shot before lapping that rolled bur off. It shoots VERY well, worrying a 3/4" Avery dot to death at 200m!

I bought the lap from Brownell's for $6. Get the lapping compound at a machine shop - a dab about the size of a seedless grape will last you for life, I recon!

P.

 

[Don M.]

Try This

Buy yourself a can of "Wipeout Bore Cleaner", and clean your barrel for
about 3 or 4 days in a row with "Wipeout" and I betcha your problems
are solved. Copper & carbon fouling is probably your problem.

 

[cookoff]

JohnD, You don't state what type of stock your rifle has. Several years past I glass bedded a new wood stocked bolt rifle. It shot great. Didn't shoot for couple of years. Next time out, groupng sucked. Played with all the usual things. Loads, mounts, scope etc. Finally tried rebedding the action in glass. Shot great. Decided the wood twisted some as it dried out in the dry deseret air where I live and changed the bedding. Don't have many wood stocks anymore for this reason.