Damm I am pissed! I have a Hill Country Rifles 7mm Rem Mag M70 (with Hart barrel) that shoots 1/2 min at 100 yards with Federal Premium 160 Trophy Bonded Tipped Loads.

Today I was horrified to see that my rifle shot a 4" group at 100 yards. I checked myself, shot again, and shot the same group. as I looked closer at the target, I could see that my bullet holes were not round but "Oval" shaped. Obviously my bullets are wobbling in flight. I couldn't believe it.

I stopped shooting and went home to inspect the gun...my first thought was that the muzzle break was loose but it did not have any mark's on it other than usual. I removed the break and inspected the crown very carefully (by eye) but I could not find any burr's, nicks, NOTHING, etc. Everything seems fine.

My only thought, since this has never happened before, is that possibly I damaged the crown while cleaning it after my last shooting session?? I use a Dewey coated rod, bore guide, brass jag, and Nylon brushes.

Could it be or do you think something else has gone wrong??

I will call Hill Country tomorrow, but it will be a sleepless night till then!!

What do you all think???

Thanks! Frank

Check the mounts,and then the scope........

If you damaged your crown you might notice evidence of bullet strikes in the b.r.a.k.e.. Sometimes a subtle strike is difficult to pick up without good light and some magnification.

Shoot it without the brake and see what happens. And check your guard screws.

Forgot to mention it but I did shoot the gun without the brake...same sized group with oval-shaped bullet holes on paper.

I don't think that guard screws would cause a bullet to wobble??

Random thoughts.

How many rounds through the barrel?

When was the last time the barrel got a good scrubbing? Try cleaning the barrel with J&B bore paste, or the Remington Bore Cleaner.

Pull one of the factory bullets and measure its diameter. Maybe these bullets are a little under correct size, and/or your barrel is a little over size.

Have you ever stuck a patch in the barrel and had to hammer the cleaning rod to get it out.
[A friend ruined a factory Remington 308 barrel this way, confirmed on a barrel makers bore scope].

My barrel is REALLY clean, and also frorgot to mention that I used rounds from different lots.

You guys don't seem to think that my bore cleaning might have done it??

Tell me you're not cleaning it from the muzzle.

The only time I have personally seen a rifle start shooting oblong holes, or perfect bullet profiles is when the barrel was "shot out".

Now in theory a bad crown, bad rifling at exit, [caused by sloppy cleaning by the muzzle, as craigster suggests], a bullet that strips the rifling and thus is not properly stabilized, [can be caused by an undersized bullet, bore relationship,or a badly fouled bore], bullet length, rifling twist incompatability, can all cause larger groups because the bylklet is not properly stabilized.

Try shooting some 140 gr bullets and see what happens. Let us know the results.

You say your barrel is clean, tell us how you clean it...

Are these bullets from the same batch which gve you such good accuracy before?

If not, measure the length of the bullets which did shoot with good accuracy, and compare that figure with the length of the bullets which gave you the poorer accuracy.

(Note: I'm talking just bullet length, not overall cartridge length.)


If these recent bullets are longer than the earlier, good-shooting ones, it may well be that your barrel twist is not sufficiently quick to completely stabilize the new bullets...and then they may wobble in flight.

Even bullets with the same name from the same maker sometimes change slightly in length and/or ogive profile if his old bullet-making dies have been replaced with new ones.

quote:

Originally posted by Leopardtrack:
I don't think that guard screws would cause a bullet to wobble??

They won't cause bullets to wobble, but they will sure as hell cause groups to open.

If the groups were shooting great one day and then suddenly opened with bullets flying sideways, using the same ammo as before, then it almost sounds like what would occur if you suddenly bulged the barrel at the muzzle. Sometimes a subtle bulge will appear just inside the muzzle that can be very difficult to detect even by experienced gunsmiths. I had one such bulge years ago that nearly drove me mad.

I just knew there was a bulge present in this customers barrel but I couldn't see it. I scoped it, I prodded, and poked it to no avail. It wasn't until I poured a cast of the muzzle and measured it. Sure enough, it was right at the muzzle. The crown and everything else looked great. It was just a little oversized. Wouldn't hurt to look. That WILL cause bullets to fly off center and groups to suddenly open.

Try another lot or original lot of ammo before pulling more hair out. If handloads can vary, imagine what can differ between factory runs...

If all else fails -- listen to malm!

Did the barrel have oil in it from the cleaning session before you shot it?

This problem showed up on the 204 Ruger rifle that I made in the top post in Stockmaker Show and Tell. I had a Krieger #2 barrel that was shooting great and I had 4 shots at 200 yds in .770 group. The next 3 shots didn't hit the paper so I quit and returned home to clean the barrel. There wasn't any swell on the outside so a wet patch was pushed down the barrel from the chamber end. I could feel a small area that was different. After a close look from the muzzle end you could see a couple of small shadows about 6 in. from the end of the crown. I had never had a problem like this before. I contacted Krieger and asked if they had any steel which could have defects. Their reply was NO and for $405 they would replace the original barrel which I had won at the 60th Anniv. at TSJC. I replaced it with a Shilen which was a lot less dollars and it shoots as well if not better than the Krieger.

For a barrel to have this kind of damage inside here is some of the posibility. Bad steel, too much oil inside after I cleaned the barrel after the first 4 shots, or a part of a cleaning patch stayed inside. A few strings of a patch probably was the problem. I now check the barrel bore much closer after cleaning. I don't think you could damage a barrel that much with your type of cleaning rod. If you can't feel a spot inside with a wet patch then I would cast about 2 inches of the muzzle end. Look for shadows inside the barrel after you have cleaned and dry patched the inside.

Here is another story on barrels. I had 3 matched oct. ribbed barrels made overseas and fitted to Weatherby Mk5's in the mid '70's. I had to stock these rifles. 257 Wea., 300 Wea. , 375 H.& H. The 257 Wea. would not group less than about 12 inches @100 yds. After several rounds were fired I cast the barrel and found that it was rifled out of round. These were cut rifled in Europe some where. One side was cut with the wrong size hook cutter which made it much larger. Replaced the barrel and it grouped about 1 inch.

My 2 cents worth

Les

I might try different ammo before I would think that my gun was ruined by cleaning. This isn't the first thread I have seen about issues with Federal premium.

http://castboolits.gunloads.co...ex.php/t-115176.html

You might as well go thru and pull the scope and check your bases also at this point and pull the action from the stock.
These suggestions have nothing to do with the oblong holes in the paper though. (were you square with the target?).


I have had rifles do the same thing to me and in one situation the scope was having internal problems.

I hate it when this happens. Good luck and let us know what you find out.

By the way I dont believe you have ruined the barrel or crown unless you used a piece rebar or all-thread, which you stated you used a good cleaning rod.


Cal30

Did you switch to a long pointy bullet that your rifle will not stabilize?

Frank

You need to be a bit more specific in the info you are giving as we are all stabbing in the dark somewhat. You say you "used rounds from different lots". Does that mean they were still Federal Premium 160gr Trophy Bonded Tip which usually gave you 1/2 min groups?

If the bullet holes are oval then you have somehow damaged the barrel as others are suggesting here, maybe slightly ringing the bore back from the muzzle if the crown looks fine. Different lots of the same factory load are just not going to suddenly shoot oval. Provided your barrel has a twist no higher than 1 in 10 then it will stabilise any 7mm bullet in any reasonable velocity load.

Surely you do not clean your barrel from the muzzle, that is a cardinal sin.

Hey Fellas,
Here's the latest after speaking with Matt at Hill Country Rifles.
I faxed him the targets and he said that the bullets are definetly wobbeling in flight. Initially he felt that I somehow damaged the crown even though nothing is visable to me.
On my end I then realized that I am using a 30 cal brass Dewey Jag for my 7mm rifle...with this said, Matt then felt that for sure that because of this the oversized jag I caused abrasion and probably changed the shape of one of the lands causing the bullets to tumble. He felt that a touch-up or re-crown of the muzzle will do the trick, so I UPS'ed the rifle and also the jag to him yesterday...I'll let you all know his findings when he has a look at it.

I hope that he's right about the muzzle, and I REALLY hope that I didn't cause any damage to the bore of the Hart barrel!

BTW... everything on the gun is checked and tight, and Matt related that my barrel has plenty of twist to stabilize a 160gr 7mm bullet.

Hope my bore is OK!

Thanks fellas!

You still haven't told us if you cleaned it from the muzzle. Am also wondering just how much abrasion brass on steel can cause.

Craig,
I NEVER clean from the muzzle..Dewey coated rod, brass jag, nylon brushes with a bore guide.

I too wonder how much abrasion can occur with brass on stainless steel...hoping not too much.

quote:

Originally posted by Leopardtrack:
Craig,
I NEVER clean from the muzzle..Dewey coated rod, brass jag, nylon brushes with a bore guide.

I too wonder how much abrasion can occur with brass on stainless steel...hoping not too much.

I hope not. I have been shooting brass jacketed bullets in most of my big bores for the past few years but haven't seen issues yet.

I am curious about how you push a .308 jag into a .284 bore.
Frank

I am curious about how you push a .308 jag into a .284 bore.

With a reeeely BIG hammer!

The Dewey jag is marked ".30".

Since I ordered the rod in 7mm, I never thought to look at the jag.

It does fit the 7mm bore easily, but I do have to use thin 7mm patches....I just figured that this was normal.

Lesson learned

If you were able to swab the bore by hand with that jag, I can't see how that alone would cause any damage.

Trigger,

I hope that you're right, and I will let you all know FYI know when Hill Country calls me after inspection.

I really do think that the jag over time messed up the lands just at the very end of the muzzle.

I do recall hearing a slight "SSSS" sound when I pull the rod back out, so I think that over time the 30 cal jag changed the dimentions of the lands at the crown...I think tjhat once fully inside the bore, the jag is lined up with the rod so hoping that the damage is only at the crown.

quote:

Originally posted by Leopardtrack:

I do recall hearing a slight "SSSS" sound when I pull the rod back out

What are you part K-9? What you heard was the sound of metal on metal, or, a brass jag being dragged back through the muzzle, over the crown and down the bore. Unscrew the jag next time before retracting the rod.

I know...you're right.

I'm hoping that the damage is just to the crown.

On the up side, your gun may be handier with about 2 inches less barrel.