I was reading the Long Range Hunting board and came across an alarming thread. A guy basically welded his RUM 300 shut. Broke the bolt handle off at the range trying to open it. Took it to his gunsmith and for three hours they tried everything they could think of, but nothing worked. He ended up sectioning the rifle with a saw and finally the bolt body was able to turn. Now the ODD part. The day before he had been shooting Nosler and Berger bullets using Retumbo. The temp was 3 degrees Fahrenheit. He finished the day with no issues. He came back the next day and it was -10 Fahrenheit or a Delta of 13 degrees COLDER. He fired some and Berger 190s loaded over Retumbo.

In his words:

"Well. I destroyed my 300 RUM today.

Yesterday I was testing some load development on my 300 RUM with Berger 230 with Retumbo.

Everything went well and found a load that appeared to group well. 86.8 gr. COL of 3.600" Federal 215 primers on Hornady Brass.

The temps were 3 degrees and a slight breeze bringing the windchill temps down to -15.

I went home and loaded a few more rounds at that charge and try a couple other loads.

Today it was -10 with a 20mph wind. For some reason no one else was at the range. I fired 20 rounds of 190gr Nosler Accubonds to make sure that everything was working well and to warm myself up a bit. I am getting about 3100 fps out of the 190s with Retumbo at 91.5gr

20 rounds fired and not a single issue. I was firing a 2 rounds then I would let it sit for few minutes and fire other rifles.

About an hour into it I then switched over to the 230 grain rounds. I fired the first round. 3129fps and I couldn't lift the bolt. Something was seriously wrong. I broke off the bolt handle trying to open it at the range hitting it with my hand trying to open the action.

I took the rifle to my local smith and I attempted to get the bolt out. After three hours f trying everything under the sun, No luck."

Now I'm scared of Retumbo, although I have shot several hundred rounds with it just trying to get a feel of it in my gun. He, nor anyone else on the thread had an answer. I've heard of pressure spikes when the cartridge gets hotter, but not colder. Any advice would be greatly appreciated.

I read the same thing today....may have 1 lb. of unopened Retumbo, “for sale” .....to someone I don’t like! memtb

I'm just finishing up my first pound of Retumbo. I've used it in a couple of Senderos, a .264 Winchester Magnum and a 7mm Remington Magnum. Unimpressive accuracy results but good velocity in the.264, good accuracy and velocity in the 7mm. Nothing out of the ordinary as to high pressure indications. Outdoor temperatures have been from around 30 degrees to 55 degrees Fahrenheit.

While we're all curious as to the cause of the reported mishap, we'll likely never know.

I haven’t heard of pressure spikes with Retumbo. Has it been reported anywhere?

Curious what’s going on. Always thought it was a good powder.

DF

never had an issue with it, its all i use in my 300 rum 200gr accubonds at 3200 fps

I have never had a problem with Retumbo and have never heard of a problem like that. I would suspect something different like a wrong bullet in the box or somehow excess powder got into the case.

3100fps with the 190s and then 3129 with the 230gr round??? I think he had that puppy stoked with 91.5gr of powder, rather than the 86.8 he had been using. Lucky he's able to tell the tale.

Makes a fellow wonder. 3129 fps from a 230 gr bullet is moving right along, even for a 300 Rem Ultra Mag.

Guy

Have shot up a lot of Retumbo, never had any problems.

Still use a lot of Retumbo, in 6MM with 107 Match Kings good speed very accurate for long range.

Magnumdood, I think you screwed up some where with your reload. Rio7

Not a Retumbo issue is my bet.

What bothers me, there's no way to get a double charge with a bulky, slow powder like that. Even an overcharge will spill over the neck and you'll know.

So, it must be something else. Was there ever anything written after the fact with more info on what happened?

DF

My 7mag loves the stuff....71.5g to be exact.

An obvious overload.

I agree fully.

Would love to see the brass.

It's plain to see it's not Magnumdood from his post, he is talking about someone else.

Yeah, don't shoot the messenger...

DF

I use Retumbo in my 30X378 for years with 180's and have never had a problem. I also tried it in my Pre 64 264 Westerner but found better accuracy with Ramshot Magnum and RL-33

I had my bolt lock up on me with obvious low end powder charges. Turned out to be the brand of brass. Switched to another brass brand and solved the pressure problem. Took the charges right on up to 1 grain over book max and suffered no adversities.

Wonder if it could be some sort of under-charge? Or maybe the wrong can on the loading bench?

That's been known to happen.

If he was using a powder measure and the powder stacked, the next charge would spill powder everywhere and he would know.

I always look in the case before seating a bullet.

DF

I am not shooting the messenger or anyone else, I may have read his post incorrectly but don't think so some one screwed up on the reload. Rio7

I think you're right about that.

Just wonder what he did.

DF

The velocity makes it quite clear, that it was an overload.

Dusty,

Would you mind sharing the load for the 180 grain bullet loaded into a 30-378?

The Retumbo bottle lists a 180 grain bullet over 113 grains of Retumbo in the 30-378. My ballistics program indicates that the pressure is close to 70,000 PSI, but not quite there. It indicates that's a safe load.

I locked the bolt on an FN Mauser with an overcharge in my 6.5x55. I was able to open the bolt with some effort, the primer was blown.

We figured with QL that is was around 80K+ psi.

This sounds like a lot more presssure than that.

DF

One of the other posters on that board said his BP estimated the pressure at around 100,000 PSI.

Just some thoughts:

Light charge and S. E. E.

Last warm up load might of been a squib load, leaving a bullet in the barrel. I have seen this before.

Barrel obstruction. Snow, mud, ice. Maybe a cleaning rod left in the bore.

Wrong powder.

Overcharge

100,000psi? He is lucky the rifle did not turn into shrapnel.

Worst blow up I have seen was a Carcano. Shooting mil-surp ammo, bullets were pulled and replaced with long soft nose. Case mouths were loose. A live round was chambered, then ejected. The bullet stayed in the throat, not noticed. Next round chambered had another bullet ahead of it! Pieces of steel and stock splinters everywhere. The shooter was badly burned over the face.

He stated the velocity reading on the shot fired, so obviously not a obstructed barrel.

Several...dozen years ago I was visiting with a custom action manufacturer who just happened to pick Bryan, TX to open up shop. We talked about a lot of things, but I mainly listened. He told me he proofed his actions at 200,000 PSI. I think he said his proofing was among the highest, but, other manufacturers sometimes proofed theirs to 100,000 PSI. At the time I had already purchased a Hall G action. If I've ever seen an action that absolutely would not come apart it was that Hall G action. It might destroy the bolt and barrel, sending one down range and the other through the shooters head, but the main part of the action would survive a nuclear strike.

I had to vigorously "tap" the bolt handle on that Hall G action one time. I was shooting a 30-378 using 180 grains Nosler Partitions over a charge of IMR 7828. I'm not sure why I loaded those rounds with that load of 7828, but it obviously was way too much. That wrapped up the day. I took the other rounds home and pulled the bullets and reloaded them with a sane charge of H50BMG.

I met a reloader/shooter at Dr. Kenneth Knotts gun smith shop in Castor, Louisiana not long ago. His brother had blown up a rifle. They dismantled the rest of that batch of hand loads and found that someone (probably a kid) had come along and dropped primers in the already primed brass sometime between the priming and the powder addition. So much for leaving your half finished loads unattended. Here's hoping it wasn't a saboteur. I've never thought to try an extra primer.

Wow...

That would do it.

Those primers would be like a REAL fast burning powder, probably worse than having a pinch of Bullseye in there.

DF

DF's explanation seems the most logical to me.

Damn, he screwed up somewhere, don't believe it was the powder.

I use Retumbo in my 300 win mag under 230 gr Berger OTM's at 2850 fps, also use it to drive 300 gr 338 cal Accubonds to 3000 fps, both loads are extremely accurate, stable and dependable, have never had anything weird happen using that powder.

I think he put the powder charge he was using under the 190's into the case and put the Berger 230 on top of that.

This is what I think too.

Barrels have been known to split in extreme cold and this is why many barrel makers will not do pencil thin ones out of 416 stainless. I don't know if this would affect the action too possibly it could as the steel is less resilient in extreme cold.

It'd be like the second stage booster on a Saturn V rocket.

What troubles me is that they destroyed the action. Typically you remove the barrel, or at least wreck the barrel by parting
just in front of the action to the minor dia. of the threads. use a barrel vise and an action wrench on the outside of the action.
you should be able to at least see if you set the lugs back, then maybe just replace the bolt.

just saying...