bullets coming apart

[lpreddick]

i've got a list now of bullets that come apart before reaching the target. bergers varmint 22 cal 60, 62. 64 gr do not like my 8 twist hart barrel chambered in 22br. cheek's 22 cal 63 gr makes it to the target half the time...when they do,they print a tiny hole. the bergers explode at about 50 yds and it looks like you hit a small clay pigeon...kinda cool. they shoot great in 12 and14 twist 22-250s. the cheek's shoot great in a 9 twist 223 savage( a fast twist but slower speed resulting in fewer rpms). precision ballistics 243 cal 88 gr flat base bullet shoots great in a 12 twist 6x47 lapua but puff at 50 yds out of a 6-284 8 twist kreiger. the bergers and cheek's use j-4 jackets that are a bit fragil. i think precision ballistics uses j-4s also. i've seen where some vlds and other high bc bullets don't make it to the paper also. when this event happened to me the first time, i was dumbfounded. now, i can anticipate the bullet no show when twisting and pushing light bullets fast. just an observation.

 

[markm87]

That's cool! Imagine the forces on that bullet before it lets go!

 

[MrMajestic]

Try a 110 grain V-Max in a 1:10 twist .300 Ackley Magnum at an advertised 3900 FPS. Sure am glad I wasn't shooting across my chronograph. What a cloud when they came apart! ;D

 

[dogdude]

slow'em down.

 

[jlow]

I think it is the twist of the barrel and not their MV.

 

[pcrowe]

When shooting my Tubb 2000 a few years ago with the factory Schneider barrel, 6xc 1/8 tw., I blew up Hornady 105 Amax's and Berger 115 VLD's. This didn't happen a lot, but enough to cost me dearly in a 600yd Highpower match. Both of these have thin jackets, I think and I havn't tried the new Bergers with the thicker jackets. I switched to Sierras and the bullet blow ups went away. I've seen this happen while behind the scope scoring for someone. What I remember is sort of a trail of smoke and then a puff about 50 to 75yds down range. Pretty cool to witness, but you don't want it happening to you at a match.

Phillip

 

[Rock Knocker]

Pcrowe is very correct. I was disqualified from a match because my first sighter didnt make it to the target. I shot one round in a match I paid for and had to be a bench warmer.

 

[lpreddick]

bullets spin themselves apart due to the rpms. the formula for rpm is mv x720/twist. these numbers will suprise you. slow the bullet down or spin is a bit slower and it might stay together. 63 gr cheek's come apart 50% of the time in my 8 tw 22 br at about 3500 fps, but say together in a 9 tw 223 at about 3200 fps. the difference in rpms is significant enough do cause the disentergration. if i reduce the powder charge in the 22 br i could get them to stay whole. of course accuracy will change, then i have to adjust seating depth. life is a struggle.

 

[pdhntr]

There is also another factor that contributes to bullet blow-ups.

A fire cracked or rough throat.

I have a 300 WM pd rifle that I shoot 110 v-max in. With a "fresh" chamber there are no problems with blow-ups. At around 5-600 rounds I will start getting the occasional blow-up. I usually go to a different bullet for a while. Eventually I set the barrel back and everything is fine again. No blow-ups.

I have tried polishing the throat and it helps some. But it seems as once it is fire cracked there isn't much to be done.

Jim

 

[hayboy]

Didn't see it myself but a buddy of mine said his 300 RUM would make a 168 Sierra MK blow up every once in a while.

 

[CanusLatransSnpr]

I had the same problem with 52gr Speer varmint hollow points in a 9tw 22-250. It was a rough factory Savage barrel coupled with the 9tw and they just wouldn't stay together. Some would make it to the target at 100 yds but, none would make it at 300 yds. These bullets were amazingly consistent +/- .0005" in base to ogive. Better than any Sierra bullet I've measured! I think they would be great in a "smooth" 12tw or 14tw barrel!

Mike

 

[lloydx2]

Friction = heat. Lead core gets too hot and delaminates the jacket. The thicker the jacket the more it insulates the core.

 

[Monolithicman]

May I humbly suggest a sure fire solution to this problem?

I have recently started using bullets made by GS Custom, the are solid copper lathe turned bullets. They shoot them as fast as 4700 fps and claim they will never blow apart from over spin. I am waiting on a new barrel in 223 WSSM to put this to the test, hoping to get 5000 fps from a 40g bullet, but even 4800-4900 would be sick!

They also make some heavier bullets that look fun, high BC

 

[okedoke]

it's simple math, RPM x VELOCITY =short barrel life and sometimes a grey streak or a puff of lead on hi-vel cartridges, monolithicman has it right- on. I rebarrel a .223 wssm once every year for a friend after he returns from a dog hunt, he shoots 4000+ fps & averages about 600 to 800 rds per tube. slow down a- little & save on bullets & barrels----------------------- take care craig

 

[Monolithicman]

Ah Okedoke sounds like your friend values the red mist more than his barrels Not sure I can blame him.

Yes, slowing down will solve both problems, but whats the fun in that. I say put the hammer down and use GS Bullets, they claim your barrel will last 3 times as long and you get even more speed, and never get the dread gray puff! Have your cake and eat it too!

My first 223 WSSM is a 1 in 14 twist, but if I like it I want to try a 1 in 7 and see how fast I can still push the 40g bullets, imagine if they could take 4800+ out of a 1 in 7 and then you can shoot a heavy bullet for long range That would be fun!

Just imagine a 68g .224 bullet with a BC of 0.464 leaving the muzzle at 3600 fps... That would do pretty well for long range, supersonic to 1600 yards and only 210" of drop at 1000.

Good Luck!

 

[lpreddick]

gs custom bullets. looked them up...fantastic production process, precision out the wazoo. looked at order page..."432.00/100" and some "500.00+/50"!! if this is american dollars per 100 and per 50 then vhitavhouri powder doesn't seem expensive anymore.

 

[Monolithicman]

Indeed if those prices were in dollars you talking some major cost, thankfully if you look at the top of the price column its says RAND, that is the South African currency. One RAND is about $0.12, so your 432 RAND box of bullets is actually $55.75. GS Custom is in the process of starting a manufacturing facility in the US so you will probably hear a lot more about them soon.

Plus shipping will be a lot cheaper, I paid $140 to ship about 500 of their bullets over, that same shipments cost should drop to $12-15 soon. I just want to give all the good folks here at accurateshooter the heads up because I have a felling GS will be back ordered very quickly once they get going here in the US, they already have a 4 month back order delay on bullets made in South Africa. I know I'm ordering a bunch as soon as they start taking orders!

Good luck!