azarcher10x
Well-Known Member
- Joined
- Nov 12, 2012
- Messages
- 287
I shoot the 36 gr. VG @ 4000. Do you remember what they told you for the spin limit?
Over-spinning bullet…until they come apart
- Thread starter FireFlyFishing
- Start date
Help Support Long Range Hunting Forum
lancetkenyon
Well-Known Member
I have vaporized two 6mm 85gr V-Max.
1:7" 6SST @ 3650+. 378,425 rpm was too much for the thin varmint jacket.
First shot, I didn't know what happened.
Second shot, I kept both eyes open figuring out what went down with shot #1.
Seeing a cloud of dust raise and a rainbow like shimmer about 10' off the muzzle was really cool.
1:7" 6SST @ 3650+. 378,425 rpm was too much for the thin varmint jacket.
First shot, I didn't know what happened.
Second shot, I kept both eyes open figuring out what went down with shot #1.
Seeing a cloud of dust raise and a rainbow like shimmer about 10' off the muzzle was really cool.
Last edited:
Seabeeken
Well-Known Member
I don't have the Barnes email but IIRC, I was shooting the 62 gr VG at about 3400 fps in my 8 twist. I was spinning them at about 331,000 rpms and they said the rotation limit was 328,000 rpm. They said to slow my speed to about 3100 fps and they should be ok. I moved to another bullet.
We were getting impacts on the target at 100 but they weren't making it to 300.
With a standard 22-250 8 twist you won't have any issues, I never had any trouble until I put together a MiddleStead
azarcher10x
Well-Known Member
- Joined
- Nov 12, 2012
- Messages
- 287
I've never had an issue with the 36 gr., but my varmint barrels are 1-12, so only 240,000ish. Good to know.
MagnumManiac
Well-Known Member
I have a 7" twist 22-250AI, it will shoot 50/55g Ballistic Tips just fine above 4000fps. Can't say the same for Sierra 52g HP. They do not make a 50yrd target. There are also 69g bullets out there that do not like 7" twist, notably Hornady.
So, as I did, you need to test them, there is no hard and fast rule, but when I calculated spin rates on some of these, they were all above 330,000rpm. The other bullets I have spun apart are Speer TNT in standard twists at extreme velocities.
Cheers.
So, as I did, you need to test them, there is no hard and fast rule, but when I calculated spin rates on some of these, they were all above 330,000rpm. The other bullets I have spun apart are Speer TNT in standard twists at extreme velocities.
Cheers.
FireFlyFishing
Well-Known Member
Whew…I had to dust off some algebra skills. Can someone check my math?
I looked up some load data from Hodgdon. If I were to load a 52 SMK at 3900 FPS, my RPMs at muzzle would be 351,000. I'm guessing this is pushing the envelope?
I looked up some load data from Hodgdon. If I were to load a 52 SMK at 3900 FPS, my RPMs at muzzle would be 351,000. I'm guessing this is pushing the envelope?
I get 354,545 rpms with a 1/8 twist that would destroy a lot of bullets.
FireFlyFishing
Well-Known Member
I don't think I can get this gun up to this velocity as it has a 22" barrel. Hodgon's data is from a 24".
Walk me through your formula if you don't mind.
I've blown several apart but it was after they left the muzzle before they did. Mine was caused by torched throats imo.
Last edited:
lancetkenyon
Well-Known Member
Velocity x 720, then Divide by twist rate.
FireFlyFishing
Well-Known Member
Thanks Lance. That's puts me at the same figure I had above.
MagnumManiac
Well-Known Member
I will also add I have 2 32" 7" twist 3 groove barrels here that will spin apart virtually every thin jacketed target bullet regardless of weight. I am stuck with them as they are both chambered in 22-250AI, and only a 243 Turdchester AI will clean them up correctly, or maybe a 22-284.
Lesson learned on those 2…
Cheers.
Lesson learned on those 2…
Cheers.
