Gas checks coming off in a Marlin

[nfg]

I just wasted the front skyscreens on TWO chrono's...an Oehler 33 and a Beta Chrony due to gas checks coming off and hitting the wire rod on the Beta which killed the LCD and the plastic LCD frame on the M33, but it kept on working. BOTH hits were on the right side rod or LCD frame.

This is a Marlin 336 I put a 45-70 barrel on and rechambered to 458 American x 2.20"...same case capacity as a 45-70 and same net volume with equal bullet seating depths.

I first thought it was me going crosseyed or jerking as it was the Beta that died first. When the M33 got hit I saw where the pieces hit the ground and collected them ALONG WITH the shed gas check that hit about 10' farther out. The largest piece had a perfect imopression that the gas check fit exactly plus the GC had bits of black plastic imbedded in edge.

Has anyone come across this same problem in the past?

This is the first time gas checks have come off within a few feet of the muzzle that I've encountered and I'm wondering if it has something to do with the muzzle brake or something else...I was shooting Oregon Trails 430 gr TrueShot bullets and I will contact them to see if they can shed any light on the problem...I'm NOT going to try these bullets without the brake and kill another Chrony or skyscreen or something else close by.

Thanks

[Gee_Wizz01]

I had the same issue with my 44 Mag Rossi Puma. The boolits I was using had a small shank and I was using Lyman slip on checks that don't crimp in place and I also had some Freechex which didn't fit well. I didn't hit my chrony, but I noticed them laying on the ground when I went to check my target. On the next batch I used a drop of super glue, which seemed to cure the problem. When I checked the batch of boolits which shed their checks, I found I could easily pop the check off with my fingernail.

G

[Bass Ackward]

I had a 458 X 2 with a muzzle break on it and I didn't have any special problems with GCs compared to the other 4 that didn't have a break.

Maybe you need to anneal your checks.

Sorry, I re-read and saw that you don't have that option.

[btroj]

It is a gas check fit on the bullet issue, not the rifle. The check shank is a bit loose. Not sure what you can do at this point other than make a baffle of some sort to protect the chronograph.

[nfg]

Thanks again!!!

I tried to pop off a check with my finger nail and a knife edge and couldn't and they appear to be crimped on.

I haven't slugged the barrel but now I will for certain. This is an early, micro 1/20 T 22" Marlin barrel I bought from Gun Parts Corp...I read somewhere they were a bit on the large size as far as the bore is concerned and the bullets are 0.458" OD. The check I found on the ground DIDN'T have any lands engraving on it which also seemed a bit strange, so maybe the bullet is tipping slightly as it exits the MB.

When it happened to the Beta chrony I thought it was me...that has happened a couple times and I've made extra rods out of gas welding rod, but when it happened to the M33 and I had the pieces I could see what did it...It won't be hard to make shield out of 1/8" steel plate to cover the frames on the M33, but with the rods going down inside the frames I will have to re-position them outside...it was the bottom end of the rod that whacked the LCD killing it...maybe duct tape will save the day...when I get it back.

I've tested many different caliber and brands of cast lead w/GC and they always kept the GC's on into the sand/dirt/logs...none have come off within inches of exiting the muzzle that I know of.

These loads were at the top end of the velocity...2200 plus fs.

Never a dull day when I'm out doing my thing. :shock::bigsmyl2:[smilie=w:

Luck