Any suggestions for why this case failed?

slimjim

1895ss wrote:

brass drift may be better then a wooden drift ... if you switch to Remington brass you may get rid of your problem, cause it will handle more pressure then the WW brass ... or you may have to fix that headspace problem.

I'm going to try and get a brass drift or make one out of a beveled Winchester case since its walls are so thin it might slip right in.

I think I will try the Remington Brass otherwise it looks like my best option is to get a the action tightened up. The easiest thing to do may be to get a .010 shim soldered to the breech face like gelandangan suggested. I expect getting the oversized rolling pins made and fitted would be more expense than this rifle is worth.

Thanks for the discussion it has helped me understand the problem and given me a few options.

Aloysius

Do you realy need a brass drift to remove the broken case? I usually get such a thing removed by a simple brass cleaning brush. Take a rather big one, push it in the chamber and pull it back. Almost always I find that piece of case sitting on my brush.
But on the other hand: why easy when it also goes difficult? Smile

slimjim

Aloysius wrote:

I usually get such a thing removed by a simple brass cleaning brush. Take a rather big one, push it in the chamber and pull it back. Almost always I find that piece of case sitting on my brush.

Aloysius, you motivated me to go try again. Maybe the penetrating oil had an impact. But alas, the broken case is still stuck in there.

Pumpkinslinger

Tried the lead idea, was a bit harder than I expected, hard to hold the lead in the right spot. Used a depth gauge to compare measurements and both methods got about 0.072".

Loading for my Marlins and the Pedersoli I've used both Winchester and Remington brass and never had any trouble with either. The Marlin loads are on the warm side too.

fnuser

yeah pump That's about what all I've measured come in at give or take .001" The trick on the pellet is to hold the firearm so the extractor\ejector cut is on top in a padded vise.

fnuser

you should be able to get the barrel set back for @$100 the gun smith will probably go one full rotation so if your action is 12 t.p.i. that would be about .080" actually its .083" but I round down cause its easier to squeak it on the last 5 degrees then have it loose. This way the action isn't "modified" and it the way it should have been the first time.

slimjim

Spent some more time looking where the slack was in the action. Its in the pins especially the breech block. Block to the roller pin, roller pin to the receiver. That's where most of the stack-up is. If I can bond a .010 shim to the breech block face, that takes care of most of it. I'm also switching to Starline brass. Got the broken case out. Will start a separate thread to explain the technique.

Oh, I'm using the scout scope to figure out if the gun is accurate enough to warrant paying $300 to $500 for a good set of peep-sights. My eyes are too old to shoot open sights accurately enough to be confident I have my loads right. Based on my experience so far, the barrel may be new but the action has seen better days.

slimjim

here is the topic on extraction technique.

Broken Case Extraction

slimjim

Replaced the old pins that were 0.452 with new oversize pins at 0.460. Got them from a gunsmith in Idaho. They fit the breech block just fine but the hammer block had to be reamed a touch. Reamed the receiver for a snug fit. Now instead of 0.018 excess headspace, I have 0.008. Right at the 0.072 max that fnuser suggested. Half of that is slack between the breech and hammer blocks when the trigger is down. I'm not going to fidel with it any more. The action is tight so I'm going to take it back out to the range.

Even though the pins are snug and had to be tapped in, I may have my tolerance a bit tight between the pins and the blocks because I can feel the pins rotate slightly every so often. I may just stake the pins.

Got the Starline brass which is very consistent in weight and finish. Also got some H4895 powder to use instead of Varget. I was having unburnt powder grains left in the barrel. H4895 burns slightly faster and at a lower pressure. Will see if that works better. Chamber pressure is now much less than black powder.

Will take it to the range tomorrow and run a few rounds through it.

slimjim

Rifle shoot well in the sense that the action is tight and I had no problem with case breakage, etc. Pins are staying fixed. Still some excess headspace. Primers are all proud about 0.010 and consistent with all the cases shot. Now that the action is tight, excess tolerance is showing up else where. The breech block has a small gab with the hammer falls which adds about 0.005 of slack in the action. Since I've gone this far, I know a good welder who can add some metal to the bottom of the breech so I can eliminate that gap.

H4895 powder was all consumed and not leaving unburnt grains in the barrel like Varget. Accuracy was ... well I need to work some more on the action and the loads. Here is my target at 50 yards with 40 grs of H4895 and 405gr Laser Cast Bullets.

Think it will be a few weeks before I get this one back out to the range.