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 Post subject: Cutter plate curiosity
PostPosted: Mon Sep 09, 2013 2:17 pm 
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'afternoon folks,

I had taken the Todd Watts defarbed '59 infantry to a small event a while back. There wasn't much firing, but it had numerous misfires. The caps I was using were clogging the cone and it turned out that the cone wasn't bored out (which didn't help), even though it appeared to have been. Instead, the flash channel in the cone resembled ><, with the narrow point at the middle of the cone. I dealt with that and took it to the range today to confirm that I wouldn't have any issues when I use it again in a couple of weeks.

Worked beautifully. Only two misfires (one clogged cone, and one ?) out of about 30 shots, and that's using the 4 wing caps. I still prefer the hotter caps, but it'll do. When I initially tested the rifle, I was low on powder and only put half a dozen shots through it, so this was the most it's done.

While cleaning it, I found a fair amount of build up behind the cutter plate. Eventually it probably would have started causing issues. But that triggered a thought. Of all of my Sharps (2 Armi's, 1 Garrett and the Ped), plus one Armi that I sold to partially fund the Garret, only two have build up issues. And I don't know why I didn't realize the common denominator before.

I'm wondering if those who have build up issues have the same "issue", and if those who don't have build up issues also have the same "issue".

Image
This is a front view, with the ArmiSport cutter on the left, the Ped on the right.

Image
Reverse view, AS on the left, Ped on the right.

The AS is typical of my Garrett and those that do not have build up issues. The Ped is the same as the one AS that does have build up issues.

Logically, it makes sense - there is much less "face" for the crud to get behind and lift. The Ped cutter well is .86" across, while the hole in the plate is .41" both front and back. The AS well is .83" across, the front hole is .63" while the reverse is .81".

Anyone have similar results?

Calum

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Calum Munro

40th PVI, 11th Reserves, Co F
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PostPosted: Tue Sep 10, 2013 9:26 am 
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Location: Old Northwest (Michigan)
Cal,

Thanks for posting the photos to accompany you inquiry. I am pleased to see the Armi Sport gas check (your terminology: cutter plate) flange is the exact same design as the Garrett, Shiloh and originals. This is the design created by Richard Lawrence (Sharps Rifle Mfg. Co. master armorer) to correct the problems of blow by (gas leakage) between the block face and reciever in earlier Sharps. The thin steel flange expands with the building pressure created by the igniting powder and pushes forward to seal the breech. The Ped gas check (brings back fond memories of my 'The Beast') is a much thicker steel--it is not designed to expand.

The Italians designed the Ped to rely on the gas sleeve insert to advance and seal the chamber instead. From my experience (and others, including Richard Lawrence) the gas sleeve, because it can't be removed from the chamber, will invariably freeze from rust. When my friend Bob Krouse strolled up on the skirmish line toting his Hawken two weeks ago I asked him where his 'Old Reliable' Ped was. He reported the Ped was 'paws up' because the sleeve was frozen. Despite being 16 years old, Bob's Ped looks brand new. I refer all our new recruits to him on the care and cleaning of a Sharps. Bob plans to emerse the Ped's reciever/barrel assembly in kerosene (like he and his friends did to clean their M-16's recievers in Nam) to see if it can free up the stuck sleeve. Stay tuned.

Okay, enough chat; some questions:

Were you firing blank or live rounds? Using flat base or clip tail rounds?
Where was the 'crud' accumulation located (use the clock system-12 is top; 6 bottom) and diameter (pencil erasure) and amount (1mm)
Any problems removing the block? Notice any irregular gaps-one side is more advanced than the other-on gas check before/after removing block?
Notice the scoring on the face of the Ped 'cutter plate'--the stain runs from the plate's opening upwards--this indicates gas is being expelled up and outwards. Don't know if this is due to live fire pressures or blanks--either way it shows gas/crud is blowing upwards.


Comparing the machining on the reverse side of the gas check, I am wondering if the excessive scoring in the surface metal is acting like a screen to permit excess gas-crud to sneak past and accumulate? All of my Sharps have very smooth surfaces on the reverse/flange side.
You might try the (a) O ring conversion or (b) file smooth the tooling scoring. If you are going to try (a) just review my article and experiment with doing a 'drop in' O-ring and see if the block will close without any filing of the washer-flange surface. Another thought would be to see if a Armi Sport check can be machined to fit the Ped block--this might solve a lot of headaches without having to dink around with 'bailing wire and chewing gum' half steps.

If you have more questions, I'd recommend going to the North-South Skirmish Assoc website and look up Charlie Hahn and post your questions on their forum. They shoot their Ped-Armi-Shilohs competively and have come up with more modifications for repop Sharps than anybody else I know of.

Hope this helps;

Bill Skillman
Chief Bugler, 4th Battalion (Sharpshooters) USV
Hudson Squad Mess-USSS


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PostPosted: Tue Sep 10, 2013 11:07 am 
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'morning,

Actually, one of my AS has the Richard Lawrence design, the other has the same "Italian version" as the Ped. I've not checked serial numbers to know which is earlier. The pard that I sold the most recent AS to is going to check which type his has.

For Bill's questions,
I was using clip tail blanks (I have the lead now, but haven't assembled any cartridges for the longer Ped chamber yet)
My ah-ha moment wasn't until after I cleaned it, so I didn't pay particular attention, but I believe that the crud was fairly consistent around the inside. It was definitely less than a millimeter, as it wasn't causing any seizing issues (yet).
The block came out easily, with no unusual gapping on the plate, nor was the plate unusually difficult to remove.
I didn't notice any blow by from the top of the block when firing. I'll have to check specifically for that next time I have it at the range.

The AS plate is considerably shorter than the Ped plate, so swapping isn't an option (I thought of that and tried them side by side). Also, the AS well in the block is .03" narrower than the Ped, so it wouldn't fit snuggly anyway.

I'm planning on smoothing out the back of the plate. Since the Ped already has a NSSA type O ring conversion done (see www.berdansharpshooters.com/usssbb/view ... f=32&t=277 for details), I'm going to hold off on doing Bill's O ring conversion for the time being. I'm curious how well the NSSA version will do - it definitely helps to keep the chamber sleeve free.

I'm also thinking of seeing if I can modify the Ped plate to more closely resemble the concave back of the other plates. If it doesn't work, it's a fairly simple part to get from the factory...

Calum

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Calum Munro

40th PVI, 11th Reserves, Co F
http://www.facebook.com/reserve.companyf

1st USSS, Co H
http://nyberdans.wix.com/nyberdans


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