300RUM reloading experts needed

[308 nate]

Here is what's happening. I built a couple 300RUMs for a friend of mine and he is having some problems with reloading. (no, he's not a new reloader)

New brass he can run 92grs. of Retumbo with 210 Berger's and just about 3200 FPS with no pressure and easy extraction.
Once the case is full length resized and loaded back up with the same primer, powder and bullets this load is too hot and sticks in the chamber.
It needs to be backed down to 90 grs. to be functional. reload number three is backed down to 89grs. (everything same as above.) to be functional. reload number four needs to be 88.5grs. to be functional. Velocity is about 3050fps and still a little bit sticky but will work.

Brass necks have been annealed after first firing, also done with brand new brass never annealed (other than factory).

Chamber reamer used is a match spec by Dave Kiff
there appears to be .003 clearance between the neck on a loaded round and the chamber neck. He says bullet seating tension is very consistent. I am trying to help him out and am quite frankly stumped! I haven't really loaded much for a 300RUM, never owned one and have only dealt with new brass.

Questions: Could a donut at the base of the neck be building up more on each shot causing the pressure increase??

Do I need more neck clearance on my chamber reamer??

I have build numerous 300RUM's with this reamer and have not heard of any problems other than these two.

So what are you guys doing to your brass?

Are you turning necks?

Are you reaming inside of necks??


Would sure appreciate your input and suggestions........


308nate

[jmason]

Mine's just a factory rum but I've not had this happen. I've use federal and rem brass. The federal brass stretched like crazy. the rem brass doesn't seem to as bad. I don't turn the necks for this gun either. Does he have a different lot of brass to test w/? maybe just a goofed up lot of brass? I have had 300 rum brass (rem) that was visibly goofed up before. The flash holes where not centered. I mention that only to show that there could be other goofs that escape the factory.

[Varmint Hunter]

Very interesting. I thought that I was the only one who was experiencing this problem with my recently rebarreled 300RUM. I've got a 27" Broughton 5C with a minimum spec chamber.

Handloaded (new) Federal brass ejects normally. Once fired brass reloaded with the same load needs to be tapped out with a cleaning rod. I am using Redding "S" type FL bushing dies, just pushing the shoulders back .001-.002". Swithching to a Forester match FL die did not resolve the problem. Switching to Rem brass gave the same results, OK for the first shot only.

Reducing loads to 300WBY levels was one of the few ways to get the spent cases out of the chamber w/o difficulty. I didn't chamber this rifle in 300RUM so that I could only use 300WBY equivalent loads.

One of the only ways I was able to mitigate the extraction problem was to swith to Hodgdon US869 powder. I assume that it produces less peak pressure. My accuracy load is 101.1gr 869 under a Berger 210 VLD that is loaded .020" off the rifling.

My smith tells me that he has built many rifles using the same reamer without a single complaint from anyone else. He originally thought that it was an issue with the brass but that didn't pan out.

I sure will be interested in the responses to this post.

[jmden]

Interesting. I wish I could help out. I've probably produced 1400 reloads for my 300 RUM over the years and haven't expereinced anything as drastic as that. I have noticed an increase in pressure with suceeding loadings up to about 3 or 4 loadings but still not nearly with the associated velocity changes you describe and certainly no problems (with my normal loads) with extraction, etc. Thinking......

[J E Custom]

Originally Posted by 308 nate

Here is what's happening. I built a couple 300RUMs for a friend of mine and he is having some problems with reloading. (no, he's not a new reloader)

New brass he can run 92grs. of Retumbo with 210 Berger's and just about 3200 FPS with no pressure and easy extraction.
Once the case is full length resized and loaded back up with the same primer, powder and bullets this load is too hot and sticks in the chamber.
It needs to be backed down to 90 grs. to be functional. reload number three is backed down to 89grs. (everything same as above.) to be functional. reload number four needs to be 88.5grs. to be functional. Velocity is about 3050fps and still a little bit sticky but will work.

Brass necks have been annealed after first firing, also done with brand new brass never annealed (other than factory).

Chamber reamer used is a match spec by Dave Kiff
there appears to be .003 clearance between the neck on a loaded round and the chamber neck. He says bullet seating tension is very consistent. I am trying to help him out and am quite frankly stumped! I haven't really loaded much for a 300RUM, never owned one and have only dealt with new brass.

Questions: Could a donut at the base of the neck be building up more on each shot causing the pressure increase??

Do I need more neck clearance on my chamber reamer??

I have build numerous 300RUM's with this reamer and have not heard of any problems other than these two.

So what are you guys doing to your brass?

Are you turning necks?

Are you reaming inside of necks??


Would sure appreciate your input and suggestions........


308Nate

Nate.

Giving someone like you advice Is unnerving but There is one thing that could be making the
difference that I have experienced and It would be worth a try.

Retumbo is a very unforgiving powder . It can be a great powder in some rifles and be terrible
in others. I have had it go critical with just a 2/10 grain increase while working up.

I normally work up in 1/2 grain increments and everything will be very linear (More powder,more
pressure and more velocity an then all at once they jump in velocity and pressure.

I have seen other powders do this and avoid them if I can because of temperature swings of
70 to 80 degrees in my part of the country.

There are a lot of good powders out there and I would recommend that you try one of them.
You may lose a little velocity but if the right powder is found the consistency will improve and
the load won't be as temperamental.

From what I have seen and heard your gunsmithing is second to none and the reloading
process sounds right so I would look elsewhere for the problem.

Just a thought

J E CUSTOM

[RockyMtnMT]

I have a question. Are these rifles that are having the trouble chambered with free bore or not? Would it make a difference?

Steve

[Moman]

Nate, this is a good post and one that we all will learn from. A couple things I can think of would be try case trimming to the minimum on every reloading and see if that helps. The other would be to start with new brass and mic every critical measurement, then do this again on each successive firing and see what the brass is doing. Similiar to the belted cases that need to be resized just ahead of the belt after a few firings.

Do you know where the case is sticking?