700 win mag problems

H

holl

Guest
I have a 300 Win Mag in a 700 remington. it was built by a good gunsmith, custom barrel, mcmillan stock, pillar bedded, etc. It is a heavy sporter weight rifle, vais break. I shoot it off a rest and bags and over windflags at 200yd. . It will group 3 real well and the 4th or fifth shot is 3" off. Shooting 175 g. bergers over R22. Cases are WW, neck turned, flash holes deburred, etc. I'm about to the point that I think it is recoil/shooter, but when the trigger breaks the cross hairs are right where the should be...any ideas?
 
I believe you may be trying to compare it's grouping ability to those achieved with long-range BR rigs. I believe your results are typical for that barrel contour.
 
it is pillar bedded with devcon in the receiver area and free floated in the barrel.
 
I sounds like heat. Whether or not there is some residual stress in the barrel might be a factor. Is this a target rifle? Unless you need shots 4 and 5, trying to "fix" it involves risk, and at some point, many of the lighter barrells fail to deal with heat.
 
holl,

Make sure you have enough bullet clearance in the brake. If the problem is from heat, you can expect shots 5-6-7 to hang out of the original group or continue to walk farther out of the original group. If those later shots snap back to the original group you should examine your bench technique. A bedding problem or insufficient barrel channel clearance will frequently show significant improvement with the application of a death grip on the rifle. A barrel that frustrates with heat may respond well to cryrogenic stress relief which is relatively inexpensive and doesn't seem to have any downside.

I repeat Charles' question,"Is this a target rifle?" Four or five quick shots at game are not likely to produce a different result than the first three regardless of sustained accuracy. Just quote people your three shot groups.

Greg
 
The magazine may be to long.(if it has one?) When you tighten up the screw at the recoil lug, the floor plate bottoms out on the magzine, not the bedding pillars. The screw feels tight, but the action can move a tiny amount under recoil. This will give groups of 3-2.
 
It is not a target rifle. more of a heavy sporter, light varmiter. But, there should be a explanation for flyers... It has the detachable magazine, so I cant see that it bottoms out on the mag. well. The barrel channel will allow a dollar bill to slide between it and the barrel for the lenght of the channel.
 
I have several heavy-barreled big-boomers. They are all basically as you described your rifle. They all shoot the first three shots very well and start to scatter each successive shot.

I don't know why that is. I always thought it was heat. There's a lot of powder behind a .300 mag.
 
holl said:
.......The barrel channel will allow a dollar bill to slide between it and the barrel for the lenght of the channel.
Click to expand...

The thickness of a bill isn't enough to keep a hard kicking sporter from slapping itself barrel to channel.

Greg
 
Holl:

As Mister Smith mentioned, although a custom barrel, sporter contours commonly can't handle the heat. Gunsmiths that do custom sporter/hunting rifles usually only advertise three shot group accuracy, and barrel heating after three shots in magnum chamberings could be the reason.

Prior to doing anything to rifle, my recommendation would be to continue to shoot three shot groups, and allowing barrel to cool down 10 to 15 minutes between groups. Determine where rifle shoots when bore is cold and "squeeky clean", as this is the condition you will most likely shoot your game if being used in a hunting situation.

If three shot groups point of impact changes after 10 to 15 minute cool downs, and groups are consistent and exceptable, barrel would seem to like something other than a "squeeky" clean bore. If this is the case, alter your bore cleaning technique to make fewer passes down bore when brushing or patching.

Old Cob
 
holl said:
It is not a target rifle. more of a heavy sporter, light varmiter. But, there should be a explanation for flyers...
Click to expand...

I'm sure there is one. I'd guess if you go through about 20 barrels, you'll find one that doesn't behave that way, though as Greg says, you barrel/stock clearance is cosmetic rather than functional. That *might* fix it.

I have a big 30 that will put 40 rounds down range in two clumps of 20, about 15 minutes apart (i.e., two successive relays). The group will not open up for anything except wind changes - they'll be some of those. I've shot 50 rounds betwen cleanings in an afternoon, testing loads that I load at the range, so I still can't say "50 at once."

It weighs 80 pounds and the barrel has a water jacket. Not all solutions work for every application . . .
 
I once had a .300 Win mag. It also was a Rem 700 BDL.
I shot the same way. I tried lots of recoil reduction remedies...but the best one was to trade it in on a .270 ;) Which I did.
 
holl .......

I agree with Greg about the minimal clearance of your barrel channel. I've seen this one a hundred times before. That's a condition designed to cause flyers. Hold your rifle in one hand, and smack the forearm with your other hand. If your barrel claps against the stock . . . that's just what's happening when you're shooting. Increase the stock-to-barrel clearance.
 
You probably have the wrong "rate of twist" in your barrel for the Berger VLD 175 grn bullets....Those Bergers require a 12 or slower twist barrel to make them shoot well...try a bullet matched to your barrel twist...if you know what twist you have...

Good luck

Eddie in Texas
 
If it was a twist problem I would not think it would group 3 close ... they should all be scattered...

Possibly have it looked at by the gunsmith who worked on it...
 
i often shoot my senderos in matches where we shoot 66 rounds at 500 or 600 yards. i don't have a problem with shots out of the groups
 
This may or may not be the problem.

I was formerly using one of the top barrel makers barrels. In 5 different guns and barrels all were experiencing fliers on the forth or fifth shot and subsequent groups after the barrel warmed up. The barrels also were exhibiting extreme spreads of 60 fps., with precision loaded ammo. Three of the rifles had been rebarreled several times with prior barrels shooting recurrent 10 shot strings under .4". All of the guns were pillar bedded and the barrels free floating. The shooters all were high master level shoters. I have discussed the issues with several of my gunsmith peers and others were having the same issues. I shot several hundred rounds (different loads) and several hours with a bore scope not seeing any visual annomolies. It was recommended that I slug the barrels which I did and it was quite revealing. These barrels were advertised to be consistent within .0003", tripple stress releived and hand lapped. All had very definable tight and loose spots between the throat and crown. All five of these barrels have been replaced with another manufactures barrels and are again shooting 10 shot strings in .4".

I would highly recomend you clean the barrels removing all the carbon and copper. Then slug them or have them slugged by some one who knows how to slug a barrel.
Slugging a barrel and chronographing a barrel can tell you alot of what you can't see during the testing of a new barrel.
Nat Lambeth
 
What does the smith that you laid all the money on have to say?? If I had a rifle made and it wouldn't shoot, I'd have it right back to the smith.
As far as only "needing" 3 shots, hell, you should only need one but things don't always work out that way. :)
 
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