enlarge gas port...?

[kdiver58]

I used 11.8 grains of 1680 with good luck sub-sonic. BUT you've reamed yours so your pressure and speed may be different. I loaded to an AOL of 2.170. That gave me 1050fps most of the time.

EDITED BECAUSE I'M AN IDIOT AND TYPED IN THE WRONG NUMBER IT SHOULD HAVE BEEN 11.8 .....I'M SORRY

[Flewis]

Originally Posted by kdiver58

I used 12.4 grains of 1680 with good luck sub-sonic. BUT you've reamed yours so your pressure and speed may be different. I loaded to an AOL of 2.170. That gave me 1050fps most of the time.

That's weird, I'm using 11.6 grains and getting the same velocity with 220 grain SMKs. What kind of brass are you using?

[kdiver58]

Cut down Remington .223 UMC brass cut and trimmed to 1.360

I've noticed that the fps of loads seems to be all over the place depending which gun you are shooting it from. I Chrono'd the loads. I don't know if it's the freebore area in the barrel , the OAL , the gas port alighnment ??

I weighed each load one by one trickling each one until it was right. No two M1S AR's seem to shoot the same..

I used 11.8 grains of 1680 with good luck sub-sonic. Did you ream yours out? If so your pressure and speed may be different. I loaded to an AOL of 2.170. That gave me 1050fps most of the time.

EDITED BECAUSE I'M AN IDIOT AND TYPED IN THE WRONG NUMBER IT SHOULD HAVE BEEN 11.8 .......I'M SORRY...
THAT WAS VERY STUPID ON MY PART..

[interceptor]

Loading some up with 220gn SMK's and between 11.2 and 11.8 of AA1680 now, I'll try to post my results tomorrow evening when I get back.

[320pf]

Originally Posted by interceptor

Looking for a recipe for a with Sierra 220's and AA1680 now... Any suggestions?

interceptor,

Here is the reloading data from the Sierra manual for the 300 whisper.

Sierra (the velocities are for a 10-inch barrel)
AA1680
11.7---1000 fps
12.7---1100 fps
13.8---1200 fps
14.3---1250 fps
14.9---1300 fps

320pf

[320pf]

Here are some reloading data out the the Sierra manual for 175-180 gr bullets.

These are out of a 10-inch barrel. I have also posted my 300 whisper reload data on reloadersnest. The data on the reloadersnest site are for a 16-inch rifle:

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

2400
11.6--1200
12.4--1300
13.3--1400
14.1--1500
14.6--1550

W296
12.4--1300
13.4--1400
14.4--1500
14.9--1550

AA1680
13.0--1200
14.2--1300
15.5--1400
16.7--1500
17.3--1550

320pf

[interceptor]

The results from 11.2gn AA1680 aren't worth mentioning, but 11.8gn got me pretty consistant 1030's with the 220SMK's.

I like it. Gonna try 11.9 to get as close to the trans sonic barrier as I can.