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Diagnosing a bullet strike
- Thread starter cdhknives
- Start date
Maybe Santa will put some lead fishing sinkers in your stocking 
Red Wolf egg shaped 1/8 oz. sinkers are ,315'' od.
http://www.canadiantire.ca/en/pdp/egg-sinker-0784981p.html
But personally I think the barrel is ok given the accuracy at 100 yds that you reported with supersonic loads. For sure I would not condemn a barrel because results do not jive with a theoretical bullet stability calculation. Using a 1:8 twist 10'' barrel is not ideal for subsonic accuracy. Chances would be better with a 1:7, 16'' barrel. Even then it is not obvious that accuracy will meet your expectations.
Quote-
In general, you can expect subsonic .300 Blackout loads to not be as accurate as supersonic offerings. The tests showed the overall group average of five subsonic loads in the two rifles was about an inch larger than the supersonic rounds.
-Unquote. Note that this is at 50 yds.
At 100 yds wind will have a huge impact on subsonic bullets. I would limit testing of subsonic loads to 50 yds.
Red Wolf egg shaped 1/8 oz. sinkers are ,315'' od.
http://www.canadiantire.ca/en/pdp/egg-sinker-0784981p.html
But personally I think the barrel is ok given the accuracy at 100 yds that you reported with supersonic loads. For sure I would not condemn a barrel because results do not jive with a theoretical bullet stability calculation. Using a 1:8 twist 10'' barrel is not ideal for subsonic accuracy. Chances would be better with a 1:7, 16'' barrel. Even then it is not obvious that accuracy will meet your expectations.
Quote-
In general, you can expect subsonic .300 Blackout loads to not be as accurate as supersonic offerings. The tests showed the overall group average of five subsonic loads in the two rifles was about an inch larger than the supersonic rounds.
-Unquote. Note that this is at 50 yds.
At 100 yds wind will have a huge impact on subsonic bullets. I would limit testing of subsonic loads to 50 yds.
Last edited:
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- Apr 12, 2013
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- 560
I live on a canal on the Texas Gulf Coast. Lead sinkers are not hard to find around here
...nor is rust. 
I discovered a lot of things the first time I tried to knock down a feral pig at 200 yards with my 300bo. For example, holdover is very imprecise, and a bit of random inaccuracy from unstable bullets at 50 yards is magnified many times at 200! As a plinker it was fine, but now that I'm getting serious about using it to cull varmints at the lease I need better...and for whatever reason better doesn't seem possible with this one. If I was going to cull using HV ammo I'll just go back to the 223 AR. It is a lot cheaper to plink with too! No, it's subs or the scrap bin for this one...I don't even feel right selling it off.
...nor is rust. I discovered a lot of things the first time I tried to knock down a feral pig at 200 yards with my 300bo. For example, holdover is very imprecise, and a bit of random inaccuracy from unstable bullets at 50 yards is magnified many times at 200! As a plinker it was fine, but now that I'm getting serious about using it to cull varmints at the lease I need better...and for whatever reason better doesn't seem possible with this one. If I was going to cull using HV ammo I'll just go back to the 223 AR. It is a lot cheaper to plink with too! No, it's subs or the scrap bin for this one...I don't even feel right selling it off.
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- Jan 1, 2018
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Stick the drill rod in the bore and see where it hits the brake. Index the brake a half turn. Is the point of contact at the same spot or 180 degrees from where the intersection was before indexing the brake a half turn?
If the new point of intersection is 180 degrees from where is was before the problem is the brake.
If the point of imtersection does not change the problem is the threads on the barrel. The barrel was probably threaded referenced to the OD of the barrel and the bore is probably off center of the barrel.
The barrel threading is my guess where you will find the problem. It was threaded without centering the threads on the bore.... I have seen this many times
If the new point of intersection is 180 degrees from where is was before the problem is the brake.
If the point of imtersection does not change the problem is the threads on the barrel. The barrel was probably threaded referenced to the OD of the barrel and the bore is probably off center of the barrel.
The barrel threading is my guess where you will find the problem. It was threaded without centering the threads on the bore.... I have seen this many times
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- Apr 12, 2013
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I have pretty well given up on that barrel. I did recut the muzzle threads using a brass plug and turning between centers to insure concentricity...that didn't help. It is in the 'look at later' pile as a possible build for supersonic only work, and has been replaced with a 1:7 twist Wilson Combat SS barrel...which is showing great potential if I can just get some free time away from work! The brake is working fine. Same loads of 220 grain Nosler match bullets over H110 and same brake+suppressor, shooting sub 3/4" groups at 50 yards during break in.
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