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Breach Block Issue

Posted: Wed Aug 15, 2018 12:10 am
by Broegel
Pulled the breach block on my Shiloh 74 in 40-70 SS purchased back in 97' and found some damage post match from this last weekend. I have been shooting this rifle for years in BPCR and Buffalo matches with the same load and bullet. Many rounds down range with no change in much of anything. Last time I looked nothing was going on. Now it seems something happened. All loads have been black powder and cast. Last time the block was out was last fall and its been used in only a few matches this year.








https://www.flickr.com/photos/146110457 ... en-public/

Re: Breach Block Issue

Posted: Wed Aug 15, 2018 8:10 am
by ANick
Broegel,
You might see if you can get some sharper, closer images of that face damage.
What are the load details for your rounds? What make brass? Primer?
Any signs of leaks by the primers?

I'm just guessing, but it looks like that ring of damage / marks / erosion or whatever is just larger than the primer?

Bore condition, brass failing or primer / primer pocket issues or changes...

Curious what it works out to be...

Nick

Re: Breach Block Issue

Posted: Wed Aug 15, 2018 12:26 pm
by Kirk
I've seen that before, I think its blow by on the primer cutting it. I usually drop the block every time I clean.
Anyways, it's not the end of the world, it can be replaced, and keep that one as a spare, it's got a lot of shots left.

Kirk,

Re: Breach Block Issue

Posted: Wed Aug 15, 2018 12:39 pm
by Kurt
I have a block like it with gas cuts and I think it happened when I started using pistol primers and I cut a wad of paper with the primer seating the primer so it was flush with the head and when using rifle primers I put one under the powder. This is with only this rifle I used wads under the primer and under the powder that the block has cuts.
And Lumpy Grits..... before you ask....Primer pockets are tight and the primers seat tight so a loose pocket was not the problem before you ask. :D

Kurt

Re: Breach Block Issue

Posted: Wed Aug 15, 2018 12:43 pm
by Lumpy Grits
OP-Tell us about the load you are using. Especially, the primer. I have seen this damage from pistol primers also
Listen to what Kirk says-He's an owner of Shiloh Rifle.
Gary

Re: Breach Block Issue

Posted: Wed Aug 15, 2018 7:13 pm
by Broegel
The load I have been using for about fifteen years now is Buffalo Arms resized 30-40 Krag with rims modified for the Shiloh 40-70 rim cut. Swiss 1.5 @ 59.5 grains, Lyman/Snover 40 cal. cast 30/1 tin lead, Winchester Small Pistol Primers and one .030" veg fiber wad.

I think that Kirk and Kurt are correct that its a case of gas cutting but I must admit I was not sure about that. If you enlarge the image it is very consistant with that in appearance. The brass shows no indications that something has changed even though the cases have been reloaded numerous times. I have known for years that some issues could result from the practice of using small pistol primers. I just wanted to throw out the pic to get some feedback from other Shiloh shooters. However I am somewhat suprised that it showed up at this very late date in the history of using this load. And almost over night as I do remove the block quite often. The guys I shoot with would back up the idea that I am somewhat over zealous with my gun cleaning habits. I am not worried about the condition of the block as far as shooting is concerned, like Kirk says it has many more rounds left in it. I am wondering if I need to have another one on hand.

Re: Breach Block Issue

Posted: Wed Aug 15, 2018 7:34 pm
by Lumpy Grits
Thought .30-40 used large rifle size primers :?
G.

Re: Breach Block Issue

Posted: Wed Aug 15, 2018 10:30 pm
by Broegel
Large Pistol Primers. Pretty obvious mistake on my part. Sorry.

Re: Breach Block Issue

Posted: Thu Aug 16, 2018 6:14 am
by Lumpy Grits
Use LR primers, and that damage will stop.
LR primers are taller than LP.
G.

Re: Breach Block Issue

Posted: Fri Aug 17, 2018 4:38 pm
by Kurt
I think small rifle primer pockets would be a good deal for these black powder cases. Years ago I used small rifle pockets in my .308 with Lapua brass and they were very accurate.

Re: Breach Block Issue

Posted: Fri Aug 17, 2018 5:01 pm
by Lumpy Grits
Kurt wrote:I think small rifle primer pockets would be a good deal for these black powder cases. Years ago I used small rifle pockets in my .308 with Lapua brass and they were very accurate.
Agree 110% :wink:
Smokeless primers put out way more 'brilliance' than BP primers ever did.
G.

Re: Breach Block Issue

Posted: Fri Aug 17, 2018 7:45 pm
by Broegel
This all gets back to why I started using large pistol primers in the first place. When I first got the rifle back in 97' I did a LOT of load work with several bullets, powders and primers. The best load was the one I have used all of the years since. The large pistol primer load out shot the best loads using large rifle primers in every case. At the time there was discussion as to long term effect this practice might have over time, I just never saw any real reason to worry about it. Apparently the cutting I have now many rounds and years later is the price of doing business this way. Really cant say I am all that put off by it. I will just obtain another block and keep shooting the one I have until I deem it to far gone and replace it. If the new block lasts as long as the old one did I doubt I will still be shooting by then. Actually I don't shoot this gun any more, my grandson does. I have gone to shooting my 45-70 roller with a scope as my eyes have made the iron sights a no go for me at this point. I will let him worry about what to do with the 74'. :wink: He just completed his first shoot out in Alliance at the Shagebrush and has been shooting locally here in BPCR for a couple of years now. I think the hook is set pretty good and he most likely will wind up with the rifle on down the road.

Re: Breach Block Issue

Posted: Fri Aug 17, 2018 7:56 pm
by Lumpy Grits
Please tell your grandson-OUTSTANDING :!:
Gary

Re: Breach Block Issue

Posted: Sun Aug 19, 2018 4:42 am
by Tomklinger
Kirt,
Back in the late 80's there was a company that was making primer pocket "sleeves" out of stainless that you could press into the primer pocket to allow the use of small pistol primers. I still have cases with some. You might try on line under primer pocket liners...
Tom