300RUM reloading experts needed

[308 nate]

300RUM reloading experts needed **Problem SOLVED

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]

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?

 

[Varmint Hunter]

Cartridge length is definitely not the problem. I have fired cases and cut them to minimum length as indicated in the Hornady manual, probably a bit shorter than new cases and still have the same problem.

Case head to datum line measurement on new Federal cases is 2.4660"-2.4675" using Stoney Point equipt and a good digital caliper. Once fired cases measure 2.469" and are moved back 1-2 thousandths.

Base diameter measurement on a new case measures .543" and on a once fired case .546".

Reloaded cases chamber smooth and easy, they just don't want to extract without a little encouragement. Rather than tap the bolt handle which could damage the Rem extractor, I put a rod down the barrel and lightly tap the case web which seems to work well. It would make a quick second shot in the field take a bit longer.

 

[tjonh2001]

as nate said this is a very confusing situation. i have annealed the cases, trimmed them, weight sorted. primer pockets uniformed and primer pockets deburred. as for the load we shot retumbo and h1000 also switched from 210 bergers to 200 accubonds and 215m to 250 primers. the sholders are bumped .003 with the ful length die we have also switched different dies still same results.

guys am i asking to much for this rifle to shoot 210 bergers around 3100fps? has anyone had bad results with remington rum brass?

 

[Varmint Hunter]

as nate said this is a very confusing situation. i have annealed the cases, trimmed them, weight sorted. primer pockets uniformed and primer pockets deburred. as for the load we shot retumbo and h1000 also switched from 210 bergers to 200 accubonds and 215m to 250 primers. the sholders are bumped .003 with the ful length die we have also switched different dies still same results.

guys am i asking to much for this rifle to shoot 210 bergers around 3100fps? has anyone had bad results with remington rum brass?

My current load (US869) launches the 210 VLD at just under 3,200 ft/sec and it does extract without using the rod as described. Many guys here shoot 200gr-210gr bullets at 3,200 ft/sec without any pressure and/or extraction problems at all.

 

[specweldtom]

Nate, I can't think of anything that would cause what is happening to these rifles, but I do have experience with Retumbo in a .30 x .378 Wby. It was badly overpressured in starting loads out of the Hodgdon book. I had loaded 3 rds each of 4 different powder charges, starting at 103grs, then 104grs, 105grs ( the starting load), then 110grs (1 1/2grs under max load). Bullets were 190gr Smkhp's and 215M primers. The 103gr load kicked like a mule and extracted hard. I fired the 2nd rd and it was the same thing. Both cases had flattened primers and very light ejector hole scars. I didn't fire the 3rd one. Reasoning that such a mild load might be too light (too much air in the case), causing excessive pressure spiking, I fired 1 of the 105gr (book starting load, less than 44000 cup's) with essentially the same result. I couldn't feel any difference in the 2 loads. I didn't fire any more of the Retumbo loads, but later found that 1 or more of the 3 rds I did fire had gas-cut my bolt face. I've had IMR 4350 go supernova on me with just a 1 grain change, but this stuff started out that way. When I pulled the bullets a couple of weeks later, the powder was caked so badly that I had to dig it out with a small packing hook, but only the 110gr loads had any compression at all. I've never had any other powder do that. I only load H-5010 and US 869 now. Both are fairly linear and will slowly show pressure increases. I've pretty much settled on a 200gr Nosler Accubond and US 869 powder, but haven't chronographed any of them yet. I expect 3200-3400 fps with sub-moa in there somewhere.

Bottom line is that I can't figure out what's going on with your rifles, and particularly why you have to reduce the load with each successive firing. (So much for the light load over-pressure theory), but when I'm stumped, I just try something different.

I hope someone can figure out what's going on, but in the meantime, I absolutely recommend that you try H-5010 or US 869. My experience is that they can safely equal the performance of Retumbo. I don't remember if you said which primer you're using, but 215's or 215M's will build a fire under both these powders.

One telling indicator about the strange properties of Retumbo in a big .30 is the Hodgdon book max load for .300 RUM is 86grs with a 200gr Barnes XFB, and 95.5grs with a 200gr Nos AB. Almost identical CUP's with a 9.5 gr powder charge difference under the same weight bullet? That's a 10% change in powder charge for same wt bullets!

No answers, but some suggestions. Hopefully someone can figure out what's going on.

Tom

 

[MontanaRifleman]

I find this a very interesting thread being a new owner of a 300 RUM. I am new to reloading for it so I am by no means an expert but I'll share the little bit of experience I have with it.

First I attempted to do a Gun Juice break-in while working up to max loads with two powders, Retumbo and H1000, and three bullets, 180 E-Tips, 200 AB's and 210 Bergers, as mentioned in another thread. The rifle was a slightly use Sendero. New Rem brass case necks were turned but not trimmed. I dont trim brass until it's been fired. I was getting very early pressure signs at what I guessed was maybe 3-4 grains lower than I expected to find max. I determined this was due tio the fact that I was firng these rounds through a bore that was wet brushed with Gun Juice after being cleaned, each shot. This probably doesn't have any bearing on the problem being looked at here, but just some history on what I've been experiencing.

When I discovered that the Gun Juice treatment was the source of my early pressure signs, I worked up without it, and found powder charges and velociteis to exceed what I expected by about 2-3 grains and maybe 50 fps, i.e., 97 grains of Retumbo pushing a 200 AB @ 3250 plus without pressure signs. Went back and reloaded using Type S bushing dies, necked to leave about a .1" doughnut and still no trimming but sorted by length. In most cases, bullets were seated to barely fit the mag, approx .100 of the lands for the E-Tips and AB's. I got very spotty results pressure wise. Overall I was getting more pressure signs with the same loads that seemed OK before. But I sometimes I got pressure signs (stiff bolt) and sometimes not with the same charge and bullet.

I mostly use Boretech Eliminator to clean with and it seems to leave a durable coating that is on my fingers as I type, that is almost a week old. I've been wondering if this causing a constriction in the bore?

Bottom line, I am finding load development with these powders and bullets to be very tempormental for whatever the reason. I might try some 869 for grins.

Oh what joy to have your pet load

Mark

 

[MontanaRifleman]

One telling indicator about the strange properties of Retumbo in a big .30 is the Hodgdon book max load for .300 RUM is 86grs with a 200gr Barnes XFB, and 95.5grs with a 200gr Nos AB. Almost identical CUP's with a 9.5 gr powder charge difference under the same weight bullet? That's a 10% change in powder charge for same wt bullets!

Yeah, I found that very interesting too.. what's the deal???

 

[specweldtom]

M/R, I wish I knew. This is supposed to be a great magnum rifle powder. I haven't tried it in any other rifle, but the experience I had with it, and its unpredictable performance, plus the apparent non-linearity of the charges listed in the Hodgdon manual made me just drop it and move on. I also didn't like the caking. That can't be good. The powder was new and dry, and the loads were only about a month old when I fired them.

I may be bad-rapping a good powder, but it didn't work for me at all. I even wondered if it might be one of the powders that Hodgdon mixed up or mislabeled? I've still got about 5700 grains of it, but I don't feel right about letting someone else try it if I won't use it.

I noticed that in a couple of replys they used H-1000. It was an accurate, linear powder in my rifle, but started showing pressure too early with 200gr bullets.

I sure hope someone can figure out what's going on with tjonh's rifle. I'd like to know too.

Tom