steveolkinevel
Active Member
Has anyone had much experience of using pistol powders for subsonic rifle loads? Watching ultimate reloaders latest video I'm quite interested in researching this further.
Tite Group subsonic rifle loads
- Thread starter steveolkinevel
- Start date
I wanted N320, however settled on N330 as it was available.
All loads were tested (checking for signs of tumbling) without a mod fitted in the first instance.
.308 M12 Mauser
20 inch barrel
1/11 twist
No modifications were carried out on the PPU case.
CCI large primer
Hornady 190grn Sub X
Started at 10.5 grn N330
worked down, too 8grn N330 In .5grn decrease.
All loads proved safe.
Loads above 9.5grns were super sonic
Loads 9grn and under were Sub Sonic.
8grns loads were very quiet at 940fps
8grns Zeroed at 50m were accurate <3/4 inch.
All loads were tested (checking for signs of tumbling) without a mod fitted in the first instance.
.308 M12 Mauser
20 inch barrel
1/11 twist
No modifications were carried out on the PPU case.
CCI large primer
Hornady 190grn Sub X
Started at 10.5 grn N330
worked down, too 8grn N330 In .5grn decrease.
All loads proved safe.
Loads above 9.5grns were super sonic
Loads 9grn and under were Sub Sonic.
8grns loads were very quiet at 940fps
8grns Zeroed at 50m were accurate <3/4 inch.
steveolkinevel
Active Member
Hornadys latest recipe book has data in now supporting sub sonic loads, I'm going to see if I can pick one up this weekend.
Oh, I'd like one. If you can get hold of one, please let me know how you get on. Thanks. Wherever I've looked online it says it isn't available yet.
steveolkinevel
Active Member
Sorry I ment Hodgdons not Hornady 
jthyttin
Well-Known Member
Bullet choice depends on what you want to achieve.
- regular jacketed bullets won't be expanding etc. and shooting a bunch of them in short time will usually result in MV creeping up considerably
- lead bullets would be best (maintain MV between outings and shots) but they might interfere with full power loads with jacketed bullets (lead bullets wit gas check less so)
- plated bullets are in the middle and usually need to be tested in individual rifle
- then there are pistol bullets, that are designed for velocities around 1000fps but are quite light
- specialty subsonic rifle bullets, either monometal or jacketed, usually either expand, keep the velocity variation in check or both
Isolating single variable at time, IME:
- shorter bearing surface results in less MV variation
- greater weight results in less MV variation
- less "barrel friction" (resistance as whole) results in less powder and less MV creep
Trajectories will be similar to standard velocity / subsonic 22LR, and the same rule of thumb goes: if you only want 50m or so the MV variation does not play huge role. But if you want to plink at 100 or farther, you really need to pay attention. If you go down the rabbit hole of brass modifications, you really need to mark them so that you won't mix them in full power loads. There are special reduced volume brass in market, but I don't know if you can get them in UK.
- regular jacketed bullets won't be expanding etc. and shooting a bunch of them in short time will usually result in MV creeping up considerably
- lead bullets would be best (maintain MV between outings and shots) but they might interfere with full power loads with jacketed bullets (lead bullets wit gas check less so)
- plated bullets are in the middle and usually need to be tested in individual rifle
- then there are pistol bullets, that are designed for velocities around 1000fps but are quite light
- specialty subsonic rifle bullets, either monometal or jacketed, usually either expand, keep the velocity variation in check or both
Isolating single variable at time, IME:
- shorter bearing surface results in less MV variation
- greater weight results in less MV variation
- less "barrel friction" (resistance as whole) results in less powder and less MV creep
Trajectories will be similar to standard velocity / subsonic 22LR, and the same rule of thumb goes: if you only want 50m or so the MV variation does not play huge role. But if you want to plink at 100 or farther, you really need to pay attention. If you go down the rabbit hole of brass modifications, you really need to mark them so that you won't mix them in full power loads. There are special reduced volume brass in market, but I don't know if you can get them in UK.
Smallholder
Well-Known Member
Hodgdon now has data on its site for subsonic loads - Reloading Data Center – Hodgdon Reloading Data Center
Foxyboy43
Well-Known Member
Nope - nowhere near but 7.5 to 8 gns works very well in the .308 out to about 75 yds, used it for many years and it is in their reloading guide….
tackb
Well-Known Member
Look at the pressure difference with just a primer change ! 25% increase !Nope - nowhere near but 7.5 to 8 gns works very well in the .308 out to about 75 yds, used it for many years and it is in their reloading guide….
View attachment 455847
But next to nothing on the velocity ?
Smallholder
Well-Known Member
They are not the same units, one is CUP and the other PSI.
Smallholder
Well-Known Member
I picked up a tub of RS14 to use in my 303. I just need to work out some data for it.
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