Two weeks ago shot squirrels in 35 degree weather with 22/250 8" Twist 55gr Sierra Blitz BT, blew a few squirrels up nicely . Today in 75 degrees temps shooting same load (40grs of W-W760 ) I think my bullets were fragmenting in flight ? Set up paper target,( thinking I needed to re-sight rifle in) most shots missed target(100yds then moved target to 50 yds) but ones that did hit target looked odd,is it possible the rise in temperature created increased velocity and exceeded the bullets threshold ?
Bullets fragment in flight
- Thread starter Ironworker
- Start date
I have seen Hornady 75 grain bullets self-destruct and not reach the target at 200 yards with .223 in a 1 in 7" twist barrel.
Blitz bullets are thin jackets, so it is possible. 1 in 8" is fairly fast.
Blitz bullets are thin jackets, so it is possible. 1 in 8" is fairly fast.
Curious what velocity you are pushing?
Thin jackets, dirty throat/leade, can damage jackets.
More friction from dirty barrel = more heat.
Friction and heat melt the lead core causing it to fail at High RPM.
Berger did some testing a while back. They increased jacket thickness to keep bullets from coming apart when shooting long range. http://benchrest.com/showthread.php?49336-Berger-bullet-failure-test
See post 9 at link.
The fix may be as simple as giving the barrel a good cleaning.
More friction from dirty barrel = more heat.
Friction and heat melt the lead core causing it to fail at High RPM.
Berger did some testing a while back. They increased jacket thickness to keep bullets from coming apart when shooting long range. http://benchrest.com/showthread.php?49336-Berger-bullet-failure-test
See post 9 at link.
The fix may be as simple as giving the barrel a good cleaning.
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If your load was at the upper end of velocity at 35*, could have been too much at 75*.
If I'm deveioping a load in the cooler months of the year, I will work up to high pressure signs and then go down to the next accuracy node. That's enough to be a safe warm weather load. It may need some tweaking to be accurate at warmer temps but it won't thrash bullets.
If I'm deveioping a load in the cooler months of the year, I will work up to high pressure signs and then go down to the next accuracy node. That's enough to be a safe warm weather load. It may need some tweaking to be accurate at warmer temps but it won't thrash bullets.
3800 FPS Nevada winter 26"Brux bbl
Dusty Stevens
Shiner
Too hot now. Loads change
This is right out of the Sierra manual.
" When using 50 and 55 grain Blitz bullets, we recommend that velocities be kept under the 3600 fps level to prevent potential bullet disintegration in flight. The 22-250 Remington is still one of our most popular varmint cartridges and will undoubtedly remain so for many years to come".
" When using 50 and 55 grain Blitz bullets, we recommend that velocities be kept under the 3600 fps level to prevent potential bullet disintegration in flight. The 22-250 Remington is still one of our most popular varmint cartridges and will undoubtedly remain so for many years to come".
dellet
Gold $$ Contributor
Bullet rpm is very good to know at the upper end of velocities. There are enough references out there in the varmint shooting world of 352,000 being the limit for Blitzkings that it is probably reliable. I don’t shoot that bullet so never verified.
Twist rate needs to be verified, it becomes more important than velocity at the top end.
3800 in a 1/8 is 342,000 rpm, well within the safe zone. 100 fps only brings it up to 351,000, but so does the twist rate of 7.8/1.
Combine the two and you have 360,000.
Explaining a flyer or two in a group on paper is not near as embarrassing as trying to explain to your buddies at the range why you can’t hit a full size silhouette at 300 yards. They never seem to forget it, no matter what proof you offer
Twist rate needs to be verified, it becomes more important than velocity at the top end.
3800 in a 1/8 is 342,000 rpm, well within the safe zone. 100 fps only brings it up to 351,000, but so does the twist rate of 7.8/1.
Combine the two and you have 360,000.
Explaining a flyer or two in a group on paper is not near as embarrassing as trying to explain to your buddies at the range why you can’t hit a full size silhouette at 300 yards. They never seem to forget it, no matter what proof you offer
dcali
Bullet Maker
Just a thought, but if it's generally accepted that 3800 should work (I'm no varmint hunter), if you've got access to a bore scope, you might want to run it through the chamber and see if there's any burrs that might leave the jackets particularly vulnerable to blow ups. I doubt that's it, but it's worth a look if you can.
SteveOak
Gold $$ Contributor
The lead is not going to reach the melting temperature of lead, 621.4 degrees F, in the fraction of a second of barrel and flight time prior to disintegration.
A bullet that is overspun disintegrates due to centrifugal force. There may be other precipitating factors like jacket damage but the function is disintegration due to centrifugal force.
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Read post 9 at link.
Hornady had plastic tips melt.
I have had lead smudges around the bullet hole at 100 yards, do to a bad barrel causing blowby. The 243 Sierra had a spitzer lead tip.
They probably are not blowing up but they are unstable and have some yaw. Are the bullet holes on the target slightly oval shaped? If they were blowing up you should see fragments on a target at close range 25 yards maybe). Are you sure your factory barrel has an 8 twist? I thought they came with a twist for 52--55 gr bullets?
From my Berger Reloading manual. Recommended twist rates for a 22-250. Based on the below data an 8 twist is suitable for a 75 gr. bullet. you need a 14 or faster twist for 55 gr. Not sure what they mean by faster 12? Not clear if 10 would be to much? Try some 70-75 gr bullets they have a much better BC. Not as flat shooting but they buck the wind. You would be surprised at how much better 75 gr shot at 500 yds. I'll run some number thru a ballistic program and add them to this reply.
30 gr. 15 twist or faster
40 gr 15 twist or faster
50 gr. 14 twist or faster
52 gr 14 twit or faster
55 gr. 14 twist or faster
60 gr 12 twist or faster
64 gr. 12 twist or faster
70 gr. 9 twist or faster
75 gr. 8 twist or faster
80 gr. 8 twist or faster
90 gr. 7 twist or faster
It's surprising how good the slower bullet is especially for wind drift. The 75 is a target bullet, may not expand much. Hornady or Nosler may make a 75 gr Varmint bullet. It’s surprising how good the slower 75 bullet is. The drops are with a 100 yd zero a 275 yrd zero the drops look even better with the 75 gr.
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Its a custom barrel and yes bullet hole did look a bit oval.I know Nosler says they're varmint bullets can be pushed at unlimited speed. . I mostly shoot the 75gr+ weight bullets. ..... Thanks for posting the comparisons ,I think I'll load the 75,my rifle likes those.
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AckleymanII
Gold $$ Contributor
The sierra 55g lead tip blitz is very spectacular on coyotes at 3500, no splashes, just very very dead coyotes.
I'm going to pull those bullets
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