Key holing 6mm creed after barrel cut

jwhjwh54

jwhjwh54

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Jun 13, 2017
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#1
I got my Ruger American 6mm creed cut to 16.5 and it’s now keyholing at 50 yards and all over the damn place at 100 yards if it his paper. With the suppressor, no suppressor, hornady black and precision hunter all had issues. It’s in a mdt chassis. Could the chassis cause it, maybe I didn’t tighten down the bolts enough? bad cut and thread job? I believe the Americans are 1 7:5 twist
 
#2
jwhjwh54 said:
I got my Ruger American 6mm creed cut to 16.5 and it’s now keyholing at 50 yards and all over the damn place at 100 yards if it his paper. With the suppressor, no suppressor, hornady black and precision hunter all had issues. It’s in a mdt chassis. Could the chassis cause it, maybe I didn’t tighten down the bolts enough? bad cut and thread job? I believe the Americans are 1 7:5 twist
Click to expand...
Was it shooting the same ammo correctly before it was cut down?

Some pictures might help.
 
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#3
IMG_8508.jpeg
 
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#13
jwhjwh54 said:
all over the damn place at 100 yards if it his paper. With the suppressor, no suppressor,
Click to expand...

So there was keyholeing unsuppresd and you shot it with the suppressor installed anyway?

Not a good thing.

I have had loose scopes and loose action screws, niether caused keyholes. Poi was scetcy. Lol
 
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#14
Are those pics of just the supressor or the actual crown?

OP what's is the ending barrel ø vs the threading spec? If you are 5/8-24 do you have min 18mm/0.72 inches of barrel?

There's tons of ways to mess this up, eg bad crown, not enough meat on the barrel for the threaded mount/ shoulder, simply removing too much mass as % of the total, etc which by itself may open up some bores if they aren't cut rifled.

ETA google says .60 barrel diameter? Guessing this is probably slightly thicker at 16.5 in mark, but unlikely to be 0.72.
 
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#15
Tbac ultra 7. I shot it suppressed first and saw it key holing then took it off and it still was doing it. Anyways I’m gonna talk the the smith and when I get home.

Built this gun for fun but may just part it out and build a for real custom for my son.
 
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#17
Snuby642 said:
So there was keyholeing unsuppresd and you shot it with the suppressor installed anyway?

Not a good thing.

I have had loose scopes and loose action screws, niether caused keyholes. Poi was scetcy. Lol
Click to expand...
👆 What he said ... if it's keyholing without a suppressor, I wouldn't get my suppressors in the same zip code as that barrel, until this is resolved.

Side note ... if the last thing you did broke your gun, then look first at the last thing you did.
 
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#19
We have literally seen barrels cut with hacksaw and bandsaw during velocity trials. Not only did they not keyhole, they shot pretty damned good. The crown would have to be spectacularly fucked up to cause this.

What about if your twist rate for that bullet was borderline before the cut and now you are slow enough to fall below the threshold for stabilty?

Do you have any 6CM with lighter/shorter bullets to try?

Just a WAG but maybe worth trying.
 
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#21
@jwhjwh54 - How many rounds on this 6 Creed before the cut?? If your missing the first 4-5" of rifling, 16.5" - 2.8" - 5" only leaves 8-9" to stabilize. Plus the bullet may be getting a running start at the shortened rifled section.

I hadn't really thought about it before, but useful lifespan is probably shorter on short barrels for these barrel burning calibers.
 
#22
About 40 rounds before I cut it . the swaro and adm mount were also brand new and I’ve mounted a scope or 12 before, so I dont think that’s causing the POI shift. There is a long thread of guys shooting 6mm creedmoors so I think it should be good to go. What’s weird is that it doesn’t look like every single round is key holing.

Anyways I’ve got a couple things from this thread I’m gonna do and see if it continues then I’m headed back to the smith. Ill report back

It’s 16.5” so there is more I can still chop off
 
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#27
Yeah it’s old fked up plywood. Y’all have given me some things to look at to get everything that could be wrong with it zerod out before I drive back to the gun smith. I’m gonna tighten everything back down, try a new scope, and if it still goes nuts I’ll go to the smith after trying all the other
 
#28
jwhjwh54 said:
Yeah it’s old fked up plywood. Y’all have given me some things to look at to get everything that could be wrong with it zerod out before I drive back to the gun smith. I’m gonna tighten everything back down, try a new scope, and if it still goes nuts I’ll go to the smith after trying all the other
Click to expand...
Please report back if your scope was causing bullets to keyhole. I gotta see that.
 
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#30
jwhjwh54 said:
Likely found the culprit? Some build up of copper or maybe rust? For less than 3-4 boxes seems like a bunch of gunk down there.
Click to expand...
Dang! What did you do with that rifle since the last session?

It looks like you did an infil with SEALS and didn't rinse the seawater out of the bore!



Can't zoom too much detail in your pics but whatever corrosion or bloom you have inside the bore looks like it grew there since the last shooting session. The bumps/nodules wouldn't be there after a fresh shot went down the bore. It might grow back if something caustic is pitted into the bore surface but even one round will take that out.

New challenge for you.... Take your rifle out one more time. Shoot just 1 or 2 rounds and take another pic of that portion of bore again. I'm betting it looks totally different. Then clean it with something that will neutralize any salts and corrosives.

Yes, your bore looks like hell and shouldn't. You probably have some surface damage to the bore. BUT, I'm still thinking that isn't causing your keyhole symptom. Lots of old mil rifles and poorly kept hunting rifles with incredibly pitted bores and shot out throats still do not key hole. They may foul and shoot like shit but will not keyhole due to that type of bore damage.

This may be like Hootsey Owl and how many licks for a Tootsie-Pop. Even if you resolve it, the world may never know.
Keep us updated.
 
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#37
We've done a lot of by-the-inch cutdown tests and we bandsaw the barrel then hit it with a chamfer/deburr tool from the reloading bench. Never seen issues with stability or keyholing in doing that.

HOWEVER, we do have slow-motion footage of some sub-X's getting some pretty impressive angle of attack from AK slant brakes. You can pretty clearly see the uneven gas flow across the back of the bullet and then 5 yards down range it's wobbly bobby. So yeah, you can do it but you have to try pretty hard.
 
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#38
Ledzep said:
We've done a lot of by-the-inch cutdown tests and we bandsaw the barrel then hit it with a chamfer/deburr tool from the reloading bench. Never seen issues with stability or keyholing in doing that.

HOWEVER, we do have slow-motion footage of some sub-X's getting some pretty impressive angle of attack from AK slant brakes. You can pretty clearly see the uneven gas flow across the back of the bullet and then 5 yards down range it's wobbly bobby. So yeah, you can do it but you have to try pretty hard.
Click to expand...
This sounds like similar articles found on DTIC about devices meant to induce yaw in projectiles!
 
#39
JR1200W3 said:
He briefed a short synopsis of how much abuse a crown(or lack thereof) would take and still shoot well at a conference I attended.
Click to expand...
Publishing was encouraged for our Engineering Technician, Ballistics guy:

www.longrangehunting.com

The Over-Rated Crown

The Over-Rated Crown By Alan Marshall You probably think having a perfect crown is important to accuracy. I think so too … although this article will make you wonder. Background: I was told that one of the major chronograph manufacturers...
www.longrangehunting.com www.longrangehunting.com
 
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#44
It was that bit off rust or copper or whatever at the end of the barrel.
Walked it down to those last 3 with hornady black. Probably could get it tighter with a better rest like my original shots but it’s close enough for deer and hogs.

Swarovski Z3 3-10 scope

Now if I can stand the kinda crappy Ruger American action I’ll keep it hah



IMG_8662.jpeg
 
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