22 creedmoor: Anyone blowing up bullets with 7.5 twist?

[nmkid]

I'm shooting 80 gr. Hornady's at 3511 without any problems.

 

[284winner]

Just depends on twist and velocity. Anything under 8 twist running above 3300 and I think increases blowup percentages. My 8 twist runs 80s at nearly 3600 with no problems yet. I don't shoot fast or heat up my barrel to much. I typically run around 3500-3525 for beat accuracy. A buddy shoots a 7 twist 22-250 AI and everything he shoots out if it seem to blow up.

 

[Ned Ludd]

Does this hold true for 90gn Bergers and 95gn Sierras? I know the older Berger 90s I used to use blew up earlier than the Sierras and I was hopin the new 95gn Sierras might have been made a bit tougher to withstand the high RPMs they need?

I have a .223 Rem with a 6.8-twist barrel that has blown up both the 90 VLDs and the 88 ELDMs. It has not blown up a 90 or 95 SMK; the Sierra jackets seem a good bit tougher in my hands. However, these are loads in 6.8-twist .223 Rem that produce velocities of ~2850 fps with 88s/90s and ~2750 fps with 95s, which translates to slightly over 300K RPM for the 88s/90s. How any of these bullets will fare when they are moving at 3000 fps or above is anyone's guess.

 

[RDavies]

More so, they're a think jacket too

Think jacket?

 

[swimster]

I've been shooting some 88g Elds in my 22/250 Ai a 28inch 7 twist Brux for a while. Velocities have ran up to 3275 fps with them. I have not had any problems with them making it to the the target.

 

[Nightraider]

Think jacket?

Yup, meaning they're using another jacket jacket and drawing it more.

 

[wkdickinson]

My AR match rifle (223) with a Krieger 1:7.7 twist blows up 50gr Vmax bullets. About 8 out of 10 never make it to the target.

 

[Hohn]

There's an aspect of this that I don't think is being considered. Namely, that is the torque applied by the rifling to the bullet to try to get it to accelerate. This is a function not of speed X rpm, but of acceleration and the rate at which the RPM is changing-- rotational acceleration. A bullet this is relatively high SD (like a heavy .223) might have enough rotational inertia that the acceleration in the rifling induces little tears in the jacket. Which only get worse as the rifling abrades away more jacket at the lands.

As for how you blow up a 50gr bullet, I can only think it's acceleration plus thin jackets plus perhaps sharp rifling.

 

[Geno C]

Just something else to consider. Most custom 224 barrels are coming with a .218 bore. A lot of guys are wanting longer barrels for more speed. A bigger round running a shorter barrel with a bore of let’s say .2195”. This might make a combination that would help these bullets hold together at higher speed/rpms.

 

[Ned Ludd]

Just something else to consider. Most custom 224 barrels are coming with a .218 bore. A lot of guys are wanting longer barrels for more speed. A bigger round running a shorter barrel with a bore of let’s say .2195”. This might make a combination that would help these bullets hold together at higher speed/rpms.

Along the same line, Bartlein cuts 0.219" bore barrels and is recommending them in situations where jacket failure might be an issue.

 

[linebaugh]

Just shot a match with a guy running 88ELDs in an 8 twist at 3200 and no blow ups. Also connecting on steel to 1200 yrds.

Im still running 95 smk at 3030fps in a 7 twist and no blow ups in 1600+ rounds and the barrel gets retired in 200 more so its safe to say no blow ups there either.

 

[DIBBS]

Resurrecting an older thread.

The 22 Creedmoor may be my next coyote caliber. I will likely shoot 75 & 80 grain amaxes- and am thinking of ordering an 8 twist Bartlein barrel.

Any new info on bullet blowup, & for those that wack-n-stack a lot of varmints, targets/steel- what has your minute of vermin barrel life been?

 

[Geno C]

If all you’re running is up to 80s get an 8 twist. If your still worried about blowing up bullets get a .219 bore instead of the normal 218s you see most of the time

 

[moorepower]

My AR match rifle (223) with a Krieger 1:7.7 twist blows up 50gr Vmax bullets. About 8 out of 10 never make it to the target.

Very strange.