O ring modification

Support for the 1863 shooter. Discussions of powders, loads, bullets, etc.
Randall
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Joined: Wed Dec 14, 2005 9:45 pm

O ring modification

Post by Randall »

Somebody had a post in the not too distant past about the modification of the gas check plate for a 63 Shiloh where the protrusion on the back of the plate was ground down slightly so a square profile o ring could be used. What was the amount of material that was removed and the McMaster Carr part number for the o ring?

Thanks
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snapcap14
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Post by snapcap14 »

part # 207n70q that is what is on the package [package qty 100]
not sure the single part # is the same. will check it whe i get a chance.
don't know how much to take off to start with. would suggest you get the o-rings first and then start w/ 1/3 the thickness of the o-ring and go form there Rember you can take more off you can't put it back.
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Randall
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Post by Randall »

I did a search on the website and the part number didn't come up. What are the dimensions of the o ring and maybe I can find it that way. Is that a square profile?

Thanks
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snapcap14
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part #

Post by snapcap14 »

PART # 90025K377
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Randall
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Post by Randall »

Thanks for the help.
Charlie Hahn
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Joined: Wed Jul 12, 2006 11:38 am
Location: Maryland

Post by Charlie Hahn »

Some additional information, I have done this in the past. You need a .875 diameter o-ring about .125 thick. You grind the step so the disatnce at the bottom of the counterbore is .015 less than the diameter of the o-ring and what ever the space is between the pressure plate and the breech face, (you can find this by using a feeler gauge). The square profile o-ring works best in this application. Now, with that said, this is okay for limited use, and will over a short time leak. I does, however allow the breech to open and close better that no modification at all. You will need to change the o-ring at every cleaning and install just before shooting as sitting will allow the o-ring to take a set and reduce the preload it is intended to provide.

Charlie Hahn
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snapcap14
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preload

Post by snapcap14 »

Charlie thankfor the heads up on the preload. never thought of that.
I can get a few shoots o ut of one before i see any damage to the o-ring. but will start leaving the o-ring out until i get to the range.
Carlie I need 500 tubes 1.5" long will pick them ut at the nationals.
will send an email later
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MissedAgain
Posts: 217
Joined: Sat Jan 20, 2007 11:26 pm
Location: Aridzona

Post by MissedAgain »

:? :?

For us dummies, it would sure be great if there were pictures of the various gas check/pressure plate mods. I have read through all the posts and it is still not really clear as to what needs to be done. :? I have a feeling that I am not alone in this state of confusion.

A picture is worth a 1000 words. :wink:
'63 Shiloh
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Joined: Thu Sep 25, 2008 4:38 am
Location: Australia

Post by '63 Shiloh »

I am with Missed Again :)

Please fellers, post some pics :!:

Cheers,

Mike
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snapcap14
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Post by snapcap14 »

don't know how topost photos or i would have photo of 2 diffrent mods
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snapcap14
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Post by snapcap14 »

Standing on the ROCK
14th VA. Cav.
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'63 Shiloh
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Location: Australia

Post by '63 Shiloh »

Thank you Snap Cap.

Mate, your pics have helped greatly, appreciate it.

Cheers,

Mick
MissedAgain
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Location: Aridzona

Post by MissedAgain »

Snap Cap: Thank you for the pictures. I think they help, but since I am easily confused, I have a question.

This picture has me scratching my bald head. Is it safe to assume that this is not a Shiloh Sharps? If it is, then I am missing a part. :?

Image
MissedAgain
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Location: Aridzona

Post by MissedAgain »

Maybe this will help. I don't have a manual for the Shiloh carbine. I bought it 2nd or 3rd hand, but it appears to have been fired very little or not at all. Here's the breach block. Is anything missing?

Image
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snapcap14
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Post by snapcap14 »

from 2 diffrent sharps the first block (solid) is from my armi sport.
that i had a lot of ing. problems with we removed the clean out screw filled channel then removed the flash nipple swegged a bar into the gas check. then dirilled a streight hole from the center of the block to under the nipple. that removed about 1" fo flash channel and 2 90 deg bends.
that improved ing and shorted flash time.
one word of advice don't by an armi sport. had a lot of other problems w/ it also the hammer did not clear the nipple. w/ a cap on it the bore was so over sized i had it lined and the split chamer put in. had it back to the dealer several times was told there was nothing wrong w/ it.
the second block is from a shiloh I picked up used and the mod was already done when i got it.
your block is correct.
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