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Originally posted by org:
I've been working up loads for my RRA 16" carbine. I've found that for 55 grain bullets (Win 55FMJ, Win 55PSP, and Rem 55PSP) I can load about 27.5 grains of 748 in LC brass, WSR primers, and get about 2830 to 2860 fps. This with no signs of pressure and with good grouping, about .5 to 1.0 for the PSP bullets. Best with the Win bulk 55PSP.

My questions:

1. Is there a powder that works better (more velocity, same accuracy generally) than 748?

Answer, I use WC846 milsurp that suggests using BLC-2 loading data. I am getting 2925-2950 with 55FMJ military pulldown bullets, LC brass, and Rem 7 1/2 primers. I use 27.5 (twenty-seven and one half) grains measured on my Ohaus RCBS 505 scale. From what I can tell this powder is not as accurate as 748 in other rounds I have tried it in (30-30). It appears to be the same powder though. My BLC-2 that I have is not the same neither. These loads are out of an Oly 16"

2. I'm about .5 grains below the max recommended by several manuals, the exception being an old edition of Lymans manual which gives a 30 grain max. Will this be enough of a buffer when temps rise next summer? The loads have been developed at about 50 degrees.

Answer, As always you have to try them, My guess is that your ok, as I have had little problem with 748 in pressure spikes except in .308

3. These loads were at the max OAL the mag will accept: 2.25". Will decreasing the OAL (working up again, of course) increase or decrease velocity?

Answer, Don't know, but generally too long (into lands) or too short can effect pressure.

Currently, I'm loading the cannalure in front of the case by about .050 or so and don't plan to crimp unless the cannelure falls in the proper spot. I have a Lee factory crimp die, but found it distorts the bullets if crimped outside the cannelure. I probably crimped too heavily, but have heard opinions on both sides of whether crimping is beneficial or not. Does anyone have an opinion backed up by actual experiences such as comparison groups and/or chronograph data?

Answer, I have not crimped any AR loads to date. Can't help you there.

I plan to use the rifle for coyotes and prairie dogs, etc. I'd like to end up with a load that uses the bulk PSP bullets mentioned above, since they seem very accurate and are inexpensive.

I'm looking for opinions and knowledge from your experiences. I realize different rifles respond differently, but I'd like to hear from those who have been where I'm trying to go

You can email me at chainsaw@netnet.net and we can discuss this further or post here again.

Thanks.

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