308 load chrono

[kestak]

Sierra 2200 168 grains
LC brass
41.6 grains of I4895
Caliber 308
Shot from M1A or Howa both with 20" barels.

Is it not a little bit low velocity for that caliber/bullet that I register 20 shots from 2474 to 2502 ft/sec?

 

[cactus02]

No matter how good you are ,you cannot duplicate a laboratory. Your load is consistant and in the ball park. you are at the max in the Sierra #5 the max in sierras #1? is 42.1, and Hodgons data shows a max of 44.5gn IMR 4895 at 58000psi ( pretty hard on M1A op rod). also keep in mind most data you will see is from minimally cut chambers with a 24 or 26 inch barrel.

 

[Slamfire]

Well, sometimes stuff happens. My early data with a M1a, yes I got velocities like yours.

You have to be real careful about bumping up charges in a M1a as you can over accelerate the mechanism and that is bad is so many ways.

Also, don't use Federals in a M1a. Yes my data has federal primers, but that was before I really found out that they are too sensitive to use in this mechanism. Federals are the most slamfiring primer out there.

I recommend CCI #34 or TULA7.62, both are milspec primers

[SIZE="3"]M1A 		1/10" 6 groove Douglas		
						
							
168 Sierra Match 41.5 gr IMR4895 (thrown) LC79 Fed210S OAL 2.815		26-Mar-94
							
Ave Vel =	2429						
Std Dev =	21						
ES =	70						
Low =	2409						
High =	2479						
N =	10					
							
168 Sierra Match	42.0 grs IMR4895 (weighed) Fed 210S OAL 2.800	
							26-Mar-94
Ave Vel =	2466						
Std Dev =	24						
ES =	62						
Low =	2439						
High =	2501						
N =	10					
							
							
168 gr Sierra Match	41.5 gr AA2520 (weighed) Fed 210S OAL 2.800	
							26-Mar-94
Ave Vel =	2510						
Std Dev =	13						
ES =	41						
Low =	2490						
High =	2531			[/SIZE]

 

[kestak]

So, I see that my velocities are good. I was concerned because my come-ups up to 500 meters are not at all like the ballistic softwares.