[wyogoob]

on this one:


An obvious overpressure on the first shot of a new recipe.

The load was reduced from the published 47 grains down to 45 grains.

Never seen one this bad. The end of the case took the shape of the mauser-type extractor on the end of the bolt:

Both of these cases are (were) the same.

The case swelled up in the chamber tighter than a school moms stockin' and it took two of us with the firearm held in a Lead Sled to get the bolt to roll up. And then we had to put a leather glove and a piece of wood on the bolt a tap the wood with a hammer to back the bolt and cartridge out.

I loaded up 3 reduced load cartridges, each with .5 grains more powder. Each one had the bullet seated and was then "bagged and tagged" before proceeding with the next reduced-load cartridge. The brass was new.

There was an unusual amount of white smoke that came out of the barrel and around the receiver. My guess is part of a cleaning patch was in the barrel.

The gun seems to be OK. Good grief.

 

[Nambaster]

Where in the world do you come up with a .256 Newton? That is scary for sure. So it is basically a necked down 30-06 which the .270 is pretty much the same thing... How big of a cleaning patch does it take to cause that much pressure?

 

[waspocrew]

Yikes :shock: glad you're ok!

 

[Longgun]

>>>>>>>>>>>>>>>>>>>

The gun seems to be OK. Good grief.

:shock: ... holy shmoly... glad yer alright Goob!

Take that action to a GS for an inspection. Ive seen/experienced a few overpressured cases over the years, but !THAT! that, is insane. Could your powder thrower have "donated" a few extra grains??

 

[phorisc]

ewwwwww thats nasty stuff!

 

[Critter]

I've been reloading for over 50 years now and have never experienced something like that yet but always wonder. Glad you are OK, hate to loose the Goob.

Are you sure that you used the right powder for the charge? I think that a piece of cleaning patch would just be blown out of the barrel if any of it was left in it. I think that I would also pull the other rounds apart and inspect everything in them before I tried shooting them again.

 

[DallanC]

Yea, color me shocked too.... the amount of deformation is crazy. Good thing the action was strong enough to contain it. Let us know when you get to the bottom of it, what the problem was (faulty load data?)


-DallanC

 

[wyogoob]

Thanks everyone, I'm still going over everything. Got me. I got the recipe from the May/June 1987 Handloader magazine. The projectiles, 6.5 Nosler Partitions are the exact same diameter as the factory loads I have, 0.264". The bolt is fine, the extractor is fine, no cracks or bulges anywhere.

I cleaned a .243 with a brush and then put a patch on the brush and ran it down, and then back out of the .256 Newton....couple of times. Not a good thing to do because part, or all, of the patch can stick in the tube on the way back.

I could have over-loaded the powder and the white smoke could be oil in the barrel I didn't clean out, got distracted and didn't finish cleaning the gun properly.

I always run 2 to 4 reduced loads on a new recipe. I charge them and take a sharpie and write the charge on the case immediately. Then I seat the bullet and put the load in a little ziplock bag and write all the data on it. Then I do the same on the next reduced load, staying focused on one practice load at a time.

I'm taking the firearm out again and leaving my ADD at home, thank you. :grin:

 

[wyogoob]

:shock: ... holy shmoly... glad yer alright Goob!

Take that action to a GS for an inspection. Ive seen/experienced a few overpressured cases over the years, but !THAT! that, is insane. Could your powder thrower have "donated" a few extra grains??

I weigh every load. I'm using the scale on a RCBS ChargeMaster, calibrated, zero'd, and cross-checked for accuracy on my cocaine scale before any charging.

I haven't killed anything with this rifle yet. I have an antelope doe/fawn jerky license I want to fill. My cataracts have rendered my right eye useless. It's best if I close my right eye and only use my left eye. That's OK, story of my life, but I have to switch hands and shoot left-handed. I always shot with both eyes open but can't anymore, bad right eye makes the view blurry, even with a scope. What a pain. Shooting a handgun I'm fine, I just close my right eye. I think I'll get out my pocket knife and just dig the **** thing out.

.

 

[wyogoob]

Loaded more, changed powder from Win 760 to H-4831 and reduced the published powder charge amount by 20%. Used both new Quality Cartridge brass and more-than-once-fired Winchester brass. Shot through a chronograph.

Wow, at a 20% powder charge reduction reduction it blew the primer out of the new Quality Cartridge brass again (2680 fps) and the Winchester brass (2706 fps) was OK. The extent the primer pocket opened up was dramatic

2700 fps should be normal or a little below normal for a 125 gr Partition .256 Newton round. Bad, because I was at 80% of the published charge data, 39.0 grains vs. 49.0 grains.

I did everything over, sizing, primers, measuring OAL, measured old factory ammo, more measuring, still more measuring, smoking brass, smoking loaded ammo, weighed every round, zero this, zero that, calibrate, investigate, blah, blah, blah.

It's obvious the Quality Cartridge brass won't cut the mustard. I buy a lot of discontinued and odd-ball caliber brass from Quality and the only problem I ever encountered was a split neck once in awhile.

Any thoughts?

I hate it, I'm going back to fly tying or knitting.

.

 

[Critter]

I am not sure if you have mentioned it or not but have you ever shot a factory round out of the rifle to see what it does?

If not then you might need to do a chamber cast and slug the barrel just to see if they are within specs.

 

[wyogoob]

I am not sure if you have mentioned it or not but have you ever shot a factory round out of the rifle to see what it does?

If not then you might need to do a chamber cast and slug the barrel just to see if they are within specs.

Yeah, thanks, I might do that. For now, I have measured everything I can on factory and compared it to my reloads and they match with the exception of trim length; my trimmed cases are 0.012" shorter.

We've talked shooting some factory stuff a lot. The factory ammo I have from the 20s I won't shoot and most of the other I have is collectible full box stuff from the 40s thru 60s. It's worth quite a bit and I hate to break up a full box. I have a few odds and ends but I don't know the history behind them.

This one has really got me puzzled. The data I'm using is from tested loads in a gun exactly the same as mine; a 1916 .256 Newton with a 24" segmented parabolic rifling barrel.

.

 

[Cooky]

You might paint up a cartridge with magic marker and chamber it to see if the throat is too short and crimping the bullet in place. Can you chamber a round and extract it without pulling the bullet?
Some day I'll post some pics of the remnants of a custom 25-06 that I had a "pressure excursion" in.

 

[sagebrush]

On my 25-06 if I seat the bullet to published oal I end up with high pressure like you have but not as bad. So I have to load them a little farther out. Strange as it seams I can shoot factory rounds with no problem.

 

[wyogoob]

You might paint up a cartridge with magic marker and chamber it to see if the throat is too short and crimping the bullet in place. Did that with candle smoke. Can you chamber a round and extract it without pulling the bullet? Yes, I am am chambering, cycling, every load before I go to the range.
......................................................

comments in red

 

[wyogoob]

On my 25-06 if I seat the bullet to published oal I end up with high pressure like you have but not as bad. So I have to load them a little farther out. Strange as it seams I can shoot factory rounds with no problem.

thanks

My OAL is at what's published. The OAL on the factory loads are longer.

.

 

[BPturkeys]

Loaded more, changed powder from Win 760 to H-4831 and reduced the published powder charge amount by 20%. Used both new Quality Cartridge brass and more-than-once-fired Winchester brass. Shot through a chronograph.

Wow, at a 20% powder charge reduction reduction it blew the primer out of the new Quality Cartridge brass again (2680 fps) and the Winchester brass (2706 fps) was OK. The extent the primer pocket opened up was dramatic

2700 fps should be normal or a little below normal for a 125 gr Partition .256 Newton round. Bad, because I was at 80% of the published charge data, 39.0 grains vs. 49.0 grains.

I did everything over, sizing, primers, measuring OAL, measured old factory ammo, more measuring, still more measuring, smoking brass, smoking loaded ammo, weighed every round, zero this, zero that, calibrate, investigate, blah, blah, blah.

It's obvious the Quality Cartridge brass won't cut the mustard. I buy a lot of discontinued and odd-ball caliber brass from Quality and the only problem I ever encountered was a split neck once in awhile.

Any thoughts?

I hate it, I'm going back to fly tying or knitting.

.

My thoughts are that you have found the problem...throw that Quality Brass away now!

 

[riptheirlips]

I'm sure you are, but be careful.

 

[Cooky]

Sounds like you're covering all the bases, it'll be interesting to find out what's up.

The only things I can think of are dead-soft brass or an oversize chamber.

Is the case expanding just ahead of the base? The part that's inside the chamber shouldn't grow more than a few thousandths over the original cartridge dimensions. If it is a chamber cast is in order. Chamber casting isn't near a difficult as you would imagine, I learned the difference between a .43 Spanish and 45-70 that way once.

I asked Mr. Google and Jamison also makes brass with the correct head-stamp, Graf and Sons carries it. Then there's always the completely obnoxious option of making brass from shiny-new known-quality .270 cases (knitting starts sounding good at that point).

 

[wyogoob]

Broke my heart, but I shot one of the old factory Winchester Western 129 gr cartridges. It went fine, no signs of overpressure, around 2720 fps on the chrono. That's amazing. They were advertised to do 2760 fps and Winchester quit making .256 Newton ammo in 1939 so the cartridge was at least 75 years old!!!!!

Reloaded 8 cartridges with the same 125 gr Partitions at 80% of published max in the Winchester Western once-fired brass. Everything else was exactly the same (as far as I know.)

5 shells shot fine at 2540 fps average, no signs of overpressure. The 6th shot blew the primer out and stuck the case in the chamber. Chrono reading was 2740

makes no sense