A head scratcher

[freebird63]

I am shooting a sendero 300RUM, am shooting 210gr bergers.
At 100 yards with Retumbo, H1000 and RE25 and RE22 powders I get great groups. Then I move out to 200 yards and my groups open up quite a bit. At 100 yards I can cover 5 holes with a quarter, at 200 yards I can cover 5 holes with 4 inch circle. Do I need to mess around again with bulllet seating depths or powder charges?

[ICANHITHIMMAN]

Originally Posted by freebird63

I am shooting a sendero 300RUM, am shooting 210gr bergers.
At 100 yards with Retumbo, H1000 and RE25 and RE22 powders I get great groups. Then I move out to 200 yards and my groups open up quite a bit. At 100 yards I can cover 5 holes with a quarter, at 200 yards I can cover 5 holes with 4 inch circle. Do I need to mess around again with bulllet seating depths or powder charges?

Yes for sure you do I never test a load at less than 200 yards. Bullets are just starting to stabalize at 200 yards.

Bergers are easy though do a seating depth test with your load at 200 yards min.

[retiredcpo]

I would yes
I like you do test loads at 100 yards but only to elimenate some powders
I load up 6 or 7 differant loads, 12 rounds each I shot one three shot group of each then compare them and toss the worst one or two and repeat the process
I take the best two or three loads and load 12 to 16 more rounds and reapeat again at 200 yards.
I agree with ICANHITHIMMAN you need to test at 200 yards but I dont think a load that wont shoot under 1 in at 100 yards will get any better at 200

[freebird63]

I am fairly certain that I am going to go with retumbo, partially because I have an 8lb jug. But with my chrono the speeds are pretty consistant. I had a problem with some brass the last time out, I now know how hard that 300RUM is on brass. I found probably 12 cases that had cracks on the inside. Plus the primer pockets were getting large. I have some more loaded up at several different depths. 1. Lands, .020, .040, .060 and .080
I am also going to try some 200gr Sierra's
I like the fact that the retumbo is on the extreme powder list, so come deer season this fall and if there is snow on the ground I know the powder will still perform. I had played once with some US869 and that stuff does not like cold weather.

[royinidaho]

Originally Posted by freebird63

I found probably 12 cases that had cracks on the inside.

Cracks on the inside???? Long ways or around the case?

Either way the cracks raise some kind of a flag. Most probably a read one.

The only time I've got circumferential rings was when fire forming cases and didn't leave a neck bump resulting in excessive head space.

Justathot.

[freebird63]

Yes it seems most of the cases were ones that had been annealed and were around the whole case, the cases that were not annealed did not have the cracks. I figure by the time I get a load developed it will be time for a new barrel....might be forced into bumping it up to a 338 edge or Lapua???

[royinidaho]

What's the odds of a pic?