Hello all,
I finally got around to getting some time to post here. I mainly started shooting my rimfire rifles the majority of the time since they are much cheaper than my centerfires but also a ton of fun as well.
I mainly spend my time over at
http://www.RIMFIRECENTRAL.COM but I have been surfing the web trying to find subsonic recipes for centerfires and stumbled in this forum.
I looked into the 300 whisper but figured that I could always (maybe) get one at a later time. I thought I would try my hand with some 7.62x39 subs since I already have an SKS and MAK-90 that I could play with.
I'm waiting on the new 7.62x39 chambered FNH TSR rifle to hit the market next year but for my testing the "test bed" was my Norinco SKS.
Accuracy wasn't the biggest concern at the time but results are/were and I was rather surprised with what the SKS did. It was surprisingly accurate out to 50yrds. Well, it was hitting the water filled milk jugs anyway once I compensated for the bullet arc.
OK here are my components.
Brass- Winchester
Bullets- Lapua .308 200gr "subsonic"
Hornady .308 220gr RN
Hornady .3015 174gr FMJBT
Surplus .308 150gr M2 FMJFB
Primers-CCI Magnum
CCI Standard
Powders- IMR 4759
IMR Trailboss
Accurate 5744
Hodgdon H110
I tested both factory and Enlarged flash holes (FH's) as well as Crimped and non Crimped loads and came to several conclusions:
1) Crimping is better then non crimped.
2) The velocities jumped all over the place with the enlarged FH's when compared to the factory FH's. Crimping helped a bit but non crimped was horrible.
3) The enlarged flash holes made the brass un-usable for high velocity/pressure loads....obviously
The crimped ammo with the Factory FH's also had better consistency in velocity and accuracy over the non crimped loads with all the powders and both primers so crimped it is for future use.
Unfortunately I can't find the chrono results but that just means I get to go play on the farm again. I can say that the majority of my loads were subsonic but a few had high pressure and jammed the SKS's bolt. Yeah...that's a little TOO high of pressure.
My FAVORITE load was the 220gr bullet over 6gr of Trailboss. It was a giant CCI CB with a loud "POP" and the bullet hitting the target 50yrds away. I don't want to post anything false but I recall that it was under 1000fps.
Another fun load was the 174gr FMJBT loaded backwards with all the powder measurments I tested.
The other powders were obviously louder than the trailboss but both the 5744 and 4759 had a lot of unburnt powder. This was even with the enlarged FH and crimps.
The H110 was so-so in consistency. I'm not sure if it's due to the low powder weights, being position sensitive or both. Since I'm still learning I'll look into H110 at a later time and stick with the others.
As for future tests, I did find the Lapua D166 which is a .310 200gr FMJBT bullet so I'll be testing that ASAP. I believe it's the same bullet Lapua uses in their factory subsonic 7.62x39 loads so it will be fun to test them this fall.
I'm still looking for more recipes to try and I know that I'll be able to learn a lot from the members here.
Scott
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