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]

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]

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?

 

[freebird63]

I was suppose to go out shooting this morning, but came down with some nasty bug last night and in no way did I feel like dragging all my stuff out to the hot desert. So if all goes well today and I feel better will go out tomorrow morning, will test what I have loaded and see if that made any difference, if they are still very large groups will take some pictures and post them for everyone to comment on.

 

[bigbuck]

I was suppose to go out shooting this morning, but came down with some nasty bug last night and in no way did I feel like dragging all my stuff out to the hot desert. So if all goes well today and I feel better will go out tomorrow morning, will test what I have loaded and see if that made any difference, if they are still very large groups will take some pictures and post them for everyone to comment on.

Hi freebird,
How Hot is it in your neck of the woods ?
I've just went down the same road your going down with my 300 RUM shooting the 210 Bergers . I was trying to get all of the MV that I could . I eventually got tired of big groups running mock ten. So I went back and loaded my best but not the fastest load and tried it out to 333 YRDS and it performed well for me. I had two good loads so i'll share them with you if thats okay.

1. 85.5 grains of retumbo .020 off the lands fed 215m primer 333 yrd 3 shot group measured .619

2. 87.0 grains retumbo .020 off the lands fed 215m primer 200 Yrd 3 shot group .730

The temperature was 93 degrees the time of day was One o clock .

Have you tried some low powder charges yet ? I agree with alot of folks on this site when they say that the faster you can run them the better but i just cannot reach the same accuracey potential with my rifle running them fast.

Good luck.

BigBuck

 

[freebird63]

The hottest I have ran was 94gr retumbo and at 100 yards was getting great groups and that was .030 off the lands. So I have reduced my powder and have loaded some up at the lands, .020, .040, .060 and .080. Just for grins I loaded some 200gr sierra matchkings to see how they do and have also played with 208gr A-Max. I really don't want to go below a 200gr bullet. I am trying not to get into the mind set of shooting 168gr bullets at 3500fps. I want a bullet that will travel a long ways and be very very accurate too. I don't know of any animal that can outrun a 210gr berger traveling at 2900-3000fps.

 

[trueblue]

Freebird,
What weight are you loaded at with the Bergers on the lands?
It seems you are over pressure.
How I approached load developement is I first find my pressure point with the bullets seated on the lands, then work from there .
Go back to square one and load up some cases in half grain increments until you know where you start experiencing pressure signs.
I look for ejection marks, stiff bolt, measure the base of the brass for expansion no greater than .004, ect.
Then back off from that point and fine tune your accuracy with seating depth.
Retumbo and H1000 are both good powders for the RUM.
Also, when you resize your fired brass, take a piece that is chambering kind of stiff due to headspace. Run your sizing die down in your press to where it just bumps the shoulder enough to chamber that round easier. At that point you have bumped the shoulder. I would not use the brass you have that you described earlier .

 

[bigbuck]

Freebird,
What weight are you loaded at with the Bergers on the lands?
It seems you are over pressure.
How I approached load developement is I first find my pressure point with the bullets seated on the lands, then work from there .
Go back to square one and load up some cases in half grain increments until you know where you start experiencing pressure signs.
I look for ejection marks, stiff bolt, measure the base of the brass for expansion no greater than .004, ect.
Then back off from that point and fine tune your accuracy with seating depth.
Retumbo and H1000 are both good powders for the RUM.
Also, when you resize your fired brass, take a piece that is chambering kind of stiff due to headspace. Run your sizing die down in your press to where it just bumps the shoulder enough to chamber that round easier. At that point you have bumped the shoulder. I would not use the brass you have that you described earlier .

Good advice..

I got pressure signs @ 91.5 grains of retumbo doesn't mean you will but just an example as to how everyone's guns are a little different.

 

[freebird63]

My pressure signs don't start until I hit 95gr retumbo. The same with H1000. As for RE22 and RE25, the grains are smaller. I had tried ramshot magnum and it had mega pressure, I got rid of it in a hurry. I also tried some IMR 7828SSC, got some good groups at 100 yards.
Tomorrow will show alot. I had heard that the IMR 7828 is quite accurate in the 300RUM. I am still needing a new trigger for my gun. As soon as I can round up enough for a timney. I believe that has something to do with my groups also.