PDA

View Full Version : Cast in my M1a



Wayne S
12-20-2012, 01:46 PM
For some reason, my post to Bruce B's thread on the M1A won't go through, so I'll try this ;56343
Another range session with my M1A, Hoping to get the 311365 to group I ran a step test starting with 23.0 gn and ending at 27.0 gn of AA 2230 which I have about 15# of from a long time ago.. 25.0 gn. was the limit for grouping, 26 & 27 gn's started shooting patterns.
For comparison I also loaded the 311299 as this design shows better results that the 311365 in some of my T/C bbl's as well.
The two fliers on the 10 shot group with the 25.gn were shots # 3 & #7, These bullets were cast from a 5 cavity mold and only visually inspected. For some unknow reason 24.0 gn. didn't group ??
Both bullets were seated to within .015" of the riflings to decrease bullet jump ANDinsure resistance free chambering.-
My next outing will be with the Saeco 311, the RCBS 165 Sil. and the NOE 311-155
AND, all future tests will be 10 shot groups.

Larry Gibson
12-21-2012, 11:31 AM
Are you using a dacron filler with your AA2230 loads?

Have you chronographed the loads?

What range to the targets?

Larry Gibson

Wayne S
12-21-2012, 12:13 PM
Larry,
No, no filler, had thought about trying the PSB type filler but wasn't sure how that would react with the gas system.
No, I haven't chronograph any loads
All my testing is done at 100 yds.
It had been suggested to try 28-30 gn's of 4895 with the 311365, also to put a flat nose [ 31141] on the 311299 ??
Ain't it always something

Larry Gibson
12-21-2012, 02:51 PM
Wayne S

You are finding out what many of have; cast bullets with long unsupported pointy noses just don't do well at higher velocity. I'd bet if you had chronographed those loads you see the velocity was only in the mid 'teens. If you want to push a cast bullet higher in your M1A then a better designed cast bullet for the task such as the 311291, 311041 or the 311299. I suggest the dacron filler for loads with less than 80% loading density. I do believe you will find the 311299 over 28 - 30 gr of H4895 with a 1/2 -3/4 gr dacron filler will shoot well in your M1A as it has shot well in numerous M1As and M14s that I have used it in over the last 37 years.

Larry Gibson

Wayne S
12-21-2012, 04:24 PM
Larry,
Thank you,
my measurements show that the 311365 has 64% of it's OAL supported in the rifling and the 311299 has 72% of it's OAL supported in the rifling, shorten the OAL by using a 31141 top punch,shorten the length by .10 and the % increases to 78%
Even at 1000 fps out of a 1-8 twist T/C bbl. the 299 shoots much better than the 365.
So much for hoping the higher BC of the 365 would come in handy even at 950-1100 FPS


Wayne Smith

Larry Gibson
12-22-2012, 12:28 PM
That long unsupported nose of most spitzer designs does them in...........seems we've all learned that the same difficult way........

Larry Gibson

Wayne S
12-22-2012, 01:10 PM
I'm reminded of a quote from The Dirty Dozen "they shure look preddy, but can they fight "?
and then some get these results http://castboolits.gunloads.com/showthread.php?109707-Noe-311365-sp

missionary5155
12-30-2012, 09:06 AM
Good morning
Whenever I want to try out a new to me caliber .30 barrel I always start with the RCBS RNFP gc 180 grainer. Have yet to find a caliber .30 that would not fire it reasonably well. Well my fat throated Krags are an exception.
Mike in ILL