Over-spinning bullet…until they come apart

[FireFlyFishing]

All,

I recently bought a Tikka 1:8" twist Tikka 22-250. I threaded the barrel and will be using a can. That being said, I'm thinking this rifle and cartridge with its barrel twist may be able to spin lighter .224 bullets apart. How does one know where the threshold for velocity exist so one can avoid shredding a bullet into an expensive suppressor?

TIA

 

[Huntaddict]

A bullet spinning apart is as much about the rate of spin as it is about bullet construction. Link to a calculator is below.

IME it is pretty difficult to spin apart modern bullets. It can be done but it is pretty extreme

I personally had a 22-250 ai - 24" 1:8 twist carbon bbl - running 75 grain AMAX at 3450 - they performed just fine.

Bullet Spin Rate Calculator - Calculator Academy

Source This Page Share This Page Close Enter the muzzle velocity (fps) and the barrel twist rate into the Calculator. The calculator will evaluate the

calculator.academy

 

[Petey308]

If and when it happens, it's usually a ways out from the muzzle. I doubt you'd ever experience it in your suppressor unless the bullet was so off balance to begin with.

A lot of the time, when the bullets come apart from over-revving, they also experience excessive friction and heat transfer into the core. That melts the core to the point the structural integrity is compromised. This happens quickly, but the unscheduled rapid disassembly of the bullet still occurs after it has exited the barrel and managed to travel a ways.

What bullets are you planning on using? The thinner the jackets and the longer the bearing surface, the more susceptible it is to this sort of thing.

 

[just_jon]

If you are planning on shooting cup and core bullets, your first consideration is your intended velocity. Using that info, you can calculate your RPM and consult the bullet manufacturer for info on suggested RPM limit. Or you could jump ahead and test your load unsuppressed to see if the bullet is coming apart.

If you are running a mono, RPM is not a consideration. I am running the 35HH in a 22-250AI over 4850 fps (>350,000 rpm) without issue. The 35 Berger FB at similar speeds never made it to the 100-yard target.

 

[Quintus]

If you want be sure load and shoot em without the can and see what hits the paper. Calling the manufacturer will get you most of the way there before you make the investment. As Petey said, when they do spin open it's usually 10 to 20 feet past the muzzle, that you notice it's done, but I can't say where they actually start to come open.

 

[Mike D Texas]

I've run 50 grain VMAX bullets at 3950 in my 7 twist 22-250ai and never had one come apart.

 

[bigngreen]

I've replaced a number of brakes from bullets having their jackets compromised, baffle strikes can and will happen. Keeping your throat in good shape and fouling in check helps as well or going to a mono or a heavy jacket.

 

[Teekerguy]

I've ran 53gr Vmax in my 223AI with a 1-7 going bout 3300 and never had a issue

 

[fseaman.js]

It's RPM vs bullet construction.

It's no likely to happen for "normal" combinations.

We had someone 10 years ago or so that succeeded in blowing up a bullet by over spinning it. You might be able to find the thread with a search.

It would take something like your 1:8, a 35g V-Max and pushing it as fast as you can.

 

[Dean2]

There are LOTS of smaller calibre cup and core bullets you can over spin. The 50 grain SPSX, Spire Point Super Explosive, which is a thinner jacket than the SP version is one of them. It is made by Hornady, it has a speed limit, used to be printed right on the box, 3500 fps out of a 1:12 twist. Hornady makes the 55 grain SPSX specifically for the higher velocities of the 22-250. The same issue applies to the Speer TNT, many of the Berger line, 36 grain .224 Barnes Varmint Grenades and even some of the Nosler varmint bullets. A standard 22-250 has a 1:12 twist, jump that to a 1:8 and you jack the rpm over 40% at the same velocity.

Any bullet designed for explosive fragmentation on small targets, up to yotes, can come apart with enough twist and speed. They are RPM limited. I have intentionally pushed some hard enough in 1:7 and 1:8 barrels to vaporize them. You can sometimes see them smoke out through the scope. At their worst, nothing hits the target at 50 yards.

 

[Varmint Hunter]

I used to run a 75gr A-Max at 3,670fps in an 8 twist 22-243AI. I never "dusted" a single bullet while guys shooting at lower velocities did. I think that having a good throat and moly coated bullets helped to maintain the structural integrity of the thin jackets.

Just a thought.

 

[comfisherman]

Dusted old amax in a 22-284, could have been velocity or the barrels I was buying at the time. On one of my early 223 wssms I'd rip apart 40 grain v max as the barrel wore on, but the ballistic tips still held together. Heard the newer ones are more like the b tips. I'd be willing to bet the explosions I had were more a result of what the throat looked like when a 21 year old does dumb shot strings of max loads in a super over bore cartridge....

Wed put up sheets of tissue paper on stake stands to track the bullet spatter, as at the time we thought it was funny. We never tested all that close to the muzzle.

 

[dustbag]

I have a 7 twist 22-250. Ran 88 eldm up to 32 or 3300 without issue. My gunsmith said once the throat gets worn they probably won't make it. I shot some 175 grain browning pro hunter ammo out of a new Browning 6.8 western and 2 of the first 20 never made it to target. Gun shoots real good so?

 

[muledeerhntr]

I run 50's in an 8 twist Tikka with no problems.