Wow, that 500-bullet box is HUGE (Sierra 240 HPBTs)

[pug]

320pf the very things you are experiencing is why I dropped back to 1800 fps. In the pursuit of ever higher velocities I had a premature extraction which ruptured the case which in turn blew the extractor off, bent the bolt, broke the carrier in two, blew the bolt catch off and mushroomed the magazine. Combination of gas turned up to high and load too hot.

I will have to calculate the drop for the round nose out to 300 but I know you are correct. I believe it is like 36 inchs but will run the internal and external ballistics program and see what it says for 200 and 300 yards.

I also think the carbine is better suited for supersonic use. The gases are awfully hot coming out the port so close to the chamber which brings me to you blocking off your gas port with a gas block (perhaps turning it around backwards?). Aluminum can't stand up to the hot gas erosion and the gases will burn a hole right through the block. Ask me how I know. Steel is better choice with stainless the best. I think you already know but the OA barrels take a .760 block so either you use theirs or turn the barrel down or bore the block out. I am going to leave my Oly with opened up gas port for dedicated subsonic use and work on another barrel for supersonic use. Still would like to use those 350pf rounds :).

edited to add I meant before the round nose has less drag in the bore due to less rifling engagement not less drag in the air.

[pug]

If you were interested the drop calculated for 300 yds with a muzzle velocity of 1800 fps. 100 yard zero.

180gr SGK 36"
180gr SMK 37"
180gr SRN 42"
180gr Speer RN 42"
178gr A-MAX 37"
185gr Lapua FMJBT 36"

[320pf]

pug,

Thanks for running the balistics.

check your private messages

320pf

[redtazdog]

Balistic,energy,recoil and more to test.

http://sst.benchrest.com/

[RWBlue]

Originally Posted by Quarterbore

I don't have one yet

Up to this year, all of my 300 Whispers are non-semiauto:

uh-oh, I thought you had it all.

Any suggested loads to start with?

[320pf]

If you are looking for some sub sonic load data here is a good place to start.

http://www.accuratepowder.com/data/P...0page%2076.pdf

I have tried both the 165 and 190-180 (with 180 Sierra GK) loads using AA#9.

These loads all cycled my 16-in barrel AR (Olympic Arms barrel). The gas system on this gun in in the pistol postion and the port diameter is 0.80-in.

I shot a match last month (~200 rounds) with these loads... the gun funcioned flawlessly. I was even able to use a beta-c mag.

I have posted all of my reloading data here:

http://reloadersnest.com/frontpage.asp?CaliberID=135

My loads are all listed under "Not yet verified user loads"

Good luck and have fun

320pf

[HHI 812]

Anyone care to part with some 240 SMK your not using or could spare? Want to try some, but can't see buying a 500 pack for shooting in my single shot T/C?
Thanks,
Dennis

e-mail at dennis.madriaga@gmail.com

[RWBlue]

Originally Posted by HHI 812

Anyone care to part with some 240 SMK your not using or could spare? Want to try some, but can't see buying a 500 pack for shooting in my single shot T/C?
Thanks,
Dennis

e-mail at dennis.madriaga@gmail.com

If you were local I would hand you 5 or 10 and let you play, but when you consider time and shipping and.....

You can get 50 of them from Midwayusa, for $23.49 + shipping.

[HHI 812]

Thanks RWblue!

[RWBlue]

Originally Posted by HHI 812

Thanks RWblue!

No problem, but please post your info as you develop it. We are all learning from each other.