Shooting an AR50....................fully prepped LC brass, 35 primers. Currently getting 1 1/4" - 1 3/4" groups at 200 yards with Fed A/E  factory depending on how I'm shooitng that day. Also loading pulled M33's.

Barnes site does not list H50BMG load data for 647 grain. Does anyone have some data they would like to share?

If you are shooting AMAX 750's what distance off the lands are you running them? I've seen anywhere from 5.450 out past 5.700. Factory rounds are right at 5.425.

Thanks in advance.

Thanks for the assist.......

I have been getting MOA accuracy with factory PMC and FED A/E. I broke down and ordered a box of factory 750 AMAX and did not get good results.

I had been running 200-220 grains of 872 for sized 647 pulled surplus bullets. I ordered them sized from Pat's but wasn't satisfied so I ordered a sizer and resized them all again. I run these at the same OAL  5.425+/- as the FED and PMC factory loads. I got such strange pressure swings with the 872 that I have quit using it and started using H50. My last outing with the pulled bullets and 50BMG was MOA at 5.425" OAL with no pressure signs from 220 up to 240 grains. Best was around 230 grains, not chrono'd. If it stays good with 230 grains I'm going to start messing with pushing the bullets out and tinkering with charge weight. Don't want to change too many variables at the same time.

I now have some Barnes TSX BT 647 grainers and some 750 AMAX to try in reloads with 50BMG. I'm thinking if I run a base line with minimum published data I can have a starting point to move things around. I don't have any H869 for the Barnes 647 grain published loads so I'm trying to figure out the equivalent 50BMG load.

It looks like 210-215 is a good starting point for the 750's with 50BMG.

AR50 has a generous chamber.

Measured maximum overall length for the 750's this morning and they are at 6.000+, The factory AMAX are jumping almost 1.500". Since it seems that most folks are running them around 5.700 I'll load these to that length for starters.

I also measured cartridge OAL/bullet ogive for the pulled 647's that I sized.
5.945/1.253
5.941/1.253
5.964/1.268
5.905/1.245
5.946/1.259
5.975/1.253
5.946/1.250
I believe what I'm going to have to do first is cull bullets out of the ogive average of 1.253 eliminating the high and low. Then back these off about .050 from the lands to come up with somehere around 5.890 OAL.

Comments?

comments?

I ended up with 220 grains of AA8700 behind the Barns 647 gr with an average velocity of 2656 and 3/4 MOA using #35 primers and CBC Brass.  I felt there was room for more out of it but ran out of time.  I would drop 5% and work up from there.  In my rifle there were no signs of excess pressure and I was pleased with the accuracy.

Any updates on your loads?

I've officially dropped the 872, just not worth the effort to get consistancy. 50BMG appears to be very consistant with 5 grain increments.

Ran 750's last weekend stretched out to 5.70. Shot one 3 shot group just short of a 1" at 200. The other group was just over an inch. Very proud of that.

Ran the Barnes 647's also but could only get a 1 1/2" group. I think playing with seating depth as mentioned about will be the next move.

About to give up on the 660 ball pulls. A 3" group was all they would muster. My shooting bud told me to switch to the AP pulls, resize them and see if they shoot better. I can either take the time to move them in and out, or adjusting powder charge. Not really sure what to do first.

With Federal and PMC factory loads I'm getting around a 2" group. Hornady 750 factory loads are about the same.

Bolt lift problem has mostly gone away. I went back and resized all the brass again rotating the brass 1/3 of a turn each stroke.. Was very suprised at the effort required to do the second sizing.