300 RUM Problem

[Guest]

I'm having an issue I can't seem to put my finger on. I posted the excellent results I came to with developing the 200 AB Load a few months back. The load was with re-sized brass. I loaded some up using new brass.Two different occasions I was at the range and it wouldn't group. I mean like 3" groups. :shock: I haven't changed a thing other than new brass. Any one have an experience like this?

I'll load some using re-sized brass to compare next Range outing.

Don

 

[FOTIS]

Is it a Remington? :mrgreen: :mrgreen: :mrgreen: :mrgreen:

Seriously different powder lots maybe? Did you weigh the brass?

 

[DrMike]

Is this the same lot of powder, same lot of primers, same lot of bullets and/or same lot of brass? Changes do occur, necessitating going back to the reloading bench. I would tend to suspect a significant change in composition or profile if there is no obvious reason to suspect the rifle.

 

[Guest]

Thank God for you two guys,
Ya know I think I was in a hurry when I assembled the new brass loads. I didn't weigh the brass or the bullets. It is the same lot of primers and powder. I know I trued up the case necks etc. I have some loads remaining. Going to recheck the seat depth again. It's not the gun as I was testing US869 Saturday and had one two shot load group pretty good with the 200 AB with 100 grain charge, I'll report on that soon. It's back to the loading Bench.

I will assemble some re-sized brass loads soon and compare. I must have done something wrong.

Fotis,
I love you man, It is a Remington! :mrgreen: :mrgreen:

Don

 

[Guy Miner]

Jacket material fouling the bore?

 

[SJB358]

Hope you figure it out. Check your action screws and scope.. First place I go when stuff is going where I don't want it.

 

[Guest]

Guy,
It could be some of it. The previous Range trip I started out with a clean bore. Put 5-shots through it. That's when I initially noticed the problem not grouping. Passed it off as just me having a bad day. I didn't clean the gun this time. Went out put 6-shots with US869 through then tried my load again with new brass, same results.

I'll start over with cleaning the gun, pay closer attention to detail at the Loading Bench this time.

Don

 

[Guest]

Scotty,
I did check the scope mounts and rings this time, didn't check the action screws though, but will tonight when I get home from work.

Don

 

[SJB358]

Yeah, if it is a proven load, I would check the TQ on the screws buddy. I doubt it could be anything to do with the actual gun if it shot well before. Hope you figure it out, that always frustrates me when it happens, but it is usually something I have overlooked.

 

[DrMike]

All good suggestions, Don. Such mysteries can be frustrating. Some rifles do leave significant copper deposits, which can degrade accuracy. Many rifles tolerate a surprising amount of copper wash. However, I've run into a number that would not tolerate much copper at all. For that reason, whenever I am working up a load, I will do a thorough scrub after each load series (if the rifle has been broken in) or before casing the rifle. That way, I know I am starting from the same point (or as near as practical) with each set of data. There are some rifles that demand cleaning after each subset, and these become apparent very quickly. This seems to be more common on larger capacity cases or seriously overbore cartridges. The two biggest issues in my experience are changing lots of components and a rifle that does not tolerate copper and/or carbon deposits. The fact that the rifle appears to have shot well with the US869 loads would mitigate against a loose action screw, I would think. Still, it doesn't hunt a thing to verify this point; it only takes a moment and it can save a lot of grief.

 

[JD338]

Don,

My first thought is a fouled boar. Give it a good scrubbing?

What are you using for a rest?

JD338

 

[Guest]

JD,
Shooting from Shooting Club Bench off the Lead Sled. I was using same set up with the Whelen during that day and shot a nice group with 225 Partitions. But have to admit the Bench was a bit wobbly. That morning was super busy with shooters and the muzzle blast was really getting to me.
It could be a combination of a couple of things.
The Benches are pretty close together too.

First thing the gun gets a good scrubbing, bore etc. Then to assemble some loads with re-sized cases then check the new brass loads.

Don

 

[JD338]

Start shooting with both ear plugs and muffs.

JD338

 

[OU812]

Don do you do any prep work to your new brass? If so did you change or omit anything? I always run new brass (necks anyways) through the resizing die for neck tension, clean up primer pockets, check length....



Bill

 

[Guest]

JD,
I always shoot that way, still was annoying.

Bill,
Yes I always do that with new Brass, especially Remington Brass.


Thanks,
Don

 

[Kodiak]

Personally, I like sightin' in off a pile of sand-bags, front and rear. I sighted-in off a friends Lead-sled a couple of years ago, and it was NOT the same POI as the sand-bags. I would try it from both types of rests.
YMMV,

Jim

 

[Guest]

Kodiak,
I have shot from both methods before. I'm good with the Lead Sled as it works for me. After I get through this issue I'm planning to go back to the bags and tripod bench rest.

Don

 

[Antelope_Sniper]

When I've had good loads go bad, it's usually something with the rifle.
Sometimes, just because the new brass has the headstamp, it doesn't mean it was made in the same factory. Try the old brass again and see if the gun shoots. If it does, you will have isolated the issue to the ammo. If not, you know it's a gremlin with the riffle.

Also check you seating die.....make sure it didn't get bumped and change the OAL.

 

[Guest]

After getting home from work I examined my new brass loads. I checked the seating depth again of the 14 rounds remaining and found six that were either a little long or to deep. I noticed that with the inertia puller it seemed easy to move the bullet with very little effort. Compared it to a re-sized load and there was a big difference in neck tension.

I now believe I just ran the new case necks in my RCBS Die vs the Forester Bench Rest Die.

Don

 

[Guest]

A. Sniper,
After I get the gun cleaned that's the route I'm taking.

Thanks,
Don