I had a rifle built the specs on it are a McMillan a5 stock impact 737 action and supposed to be a bartlein 6mm creedmoor barrel with 7.5 twist. 20” barrel. I was shooting hornady match 108gr eld factory ammo. The scope is a zco 4-20. Took it out brand new today and I was getting keyhole impacts any ideas? The distance was 50 yards with a free hanging paper target here’s some pics
- Thread starter Bigredone86
- Start date
Remove the muzzle brake and try that. If it stops, it's the muzzle brake. If not, you can dig deeper.
Bolt on wrong side. 
Seriously, that blows.
Hopefully you can get it sorted quick, dang good lookin rifle there!
Seriously, that blows.
Hopefully you can get it sorted quick, dang good lookin rifle there!
Check the markings AND bore size on your barrel. A 6mm bullet shouldn't drop into the bore.
Put something solid behind your target like cardboard, plastic sign board, etc. This will allow you to get an accurate hole shape in the paper.
Put something solid behind your target like cardboard, plastic sign board, etc. This will allow you to get an accurate hole shape in the paper.
That’s a good idea too. I’ll check these out and keep it updated. Thank you very much
Bolt Bolt on wrong side.
Haha thanks! I’m irritated I spent months putting it together and dump all this money in it for it to shoot like this
It's marked as a 7.5 twist.
Does the fired brass come out normal or is the neck swelled noticeably ? Mis-marked barrel, either caliber or twist is really off
Yes, exactly hard to say what it really is as well as the barrel diameter
No the fired brass looks normal to me
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I think god is sending you a message
Measure od of the fired neck & compare to a loaded one.
If the bore is wrong I’d guess 25 cal.
25 Creed pictured below. .288 od on fired case.
I don’t have a way to measure the od today, however a fired case will slide all the way down the bullet of a unfired case for what that’s worth
It should slide over a bullet, but shouldn’t be a real sloppy fit.
After you check twist as suggested above, have someone bore scope it. Or just send it back to whoever chambered it & let them figure it out.
Do they all keyhole or just sometimes?
I shot 18 rounds at 50 yards since that was the closest the range allowed and only 4 even hit the paper and of the 4 3 keyholed
You may not even need to if you can see any copper shavings or obvious signs of strikes.
That's fairly awful for 50 yards, more than just the wrong twist I'd think.
Whoever built it should be diagnosing it. Whatever you figure out goes to the same ending of sending it back to the builder for a fix.
Holy Shit, 4 out of 18 round ? as close as 50.
.. if bullet not brushing against muzzle brake bore . it has to be a mismarked barrel on the bore size ? . bigger bore like a .257 bore, others have said.
I wouldn't waste any more of my time loading, and money on brass/bullets/powder till problem found .
.
Yeah, really.
Yo, @Bigredone86….you need to talk to the gunsmith who built it.
If at all possible try a different bullet. I have seen batches of those bullets that were prone to vaporizing in mid air and generally doing odd things.
That would have to be one fucked up factory run of bullets ? only 4 out of 18 hitting paper @ 50 yrd. .
.
True, but they usually don't look like a crime scene chalk outline on the target.
The OP should let the builder resolve it, but my money is on the brake.
There are plenty of great builders that do not test fire. Precision measurements can be more telling than range time in most cases.
Ok got the brake off and it seems to be the right bore and twist and my bullet does as you show in yours the bullet stops half way in. I’ll try shooting it without the brake
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Why don't you want to just send it back. I think at this point many have suggested to have the builder look at it.
I do believe the problem is not going to be solved simply because you took the break off. If you were having strikes on the break, then yeah I could see the break coming off to be a solution. However that's not the case.
No offense to anyone here....
But I hate the stupid bullet test. It tells you nothing about the condition of the crown. If the crown is damaged either from cleaning or when it was done....it can cause accuracy issues and if really screwed up cause bullet failure etc....
To me the only thing the bullet test will tell you in all reality is if it's a 6mm or a 6.5mm as an example in this case. That's like using the old military 30cal bore gauges for a M1 Garand. It can give you an indicator for wear but they also can give you a false reading. If the bore size is at .3005" lets say...the gauge could give you a reading of 2. If the bore size is at .0000" then it should give you a reading of basically 0.
Take a look at the throat finish in the chamber as well.
As has been mentioned....call the smith.
If you shot it without the brake...and it shoots...either the brake isn't properly relieved or it's on too tight or too loose. Yes you can over tighten a brake and distort (constrict the bore) right at the muzzle end of the barrel. If that's the case that is a guaranteed accuracy killer. If it's loose it will vibrate and move around and cause harmonics and vibration issues and again effect accuracy.
The s/n is missing a digit. Get me the complete s/n and I can look it up. I did a look in the s/n log books and no 6mm's made that start out with 1JB7411X.
Should be 1JBxxxxx (there is 5 digits after the letters).
Did you order the barrel or the gunsmith? Or who did you get it from. That might help me and might not to look it up.
Later, Frank
Bartlein Barrels
Brad from bartlein was able to locate the serial number and it appears to be what my smith said it is. I’m going to take it back to the smith today and let him figure it out. Thank you for your help
Let us know if we can help you in any way!
To the OP!
To the OP!
Not sure if I missed it in the thread, but have you checked the optics system? I know it's unlikely at that distance, but your elevation could be adjusted way too low and the keyholes you're seeing are from ground-strike ricochets.
I only say this because a few years back I had a similar occurrence at 100m after swapping a scope or a mount, forget which one, but it was literally just an elevation adjustment of ~6 MILs back to normal.
Food for thought.
I only say this because a few years back I had a similar occurrence at 100m after swapping a scope or a mount, forget which one, but it was literally just an elevation adjustment of ~6 MILs back to normal.
Food for thought.
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