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View Full Version : 1863 Pedersoli Sharps Sporting rifle breechblock/cart mods



6mmintl
07-29-2008, 06:57 PM
1863 Pedersoli sporting rifle

I picked up a 1863 Pedersoli Sharps Sporting rifle on Gunboards in new condition and have started down the road to insuring the gas plate is functional and trying out a few ideas.

http://pic20.picturetrail.com:80/VOL149/8996569/19640107/327849647.jpg
http://pic20.picturetrail.com:80/VOL149 ... 849647.jpg (http://pic20.picturetrail.com:80/VOL149/8996569/19640107/327849647.jpg)

After pulling down the breech block I found the gas-plate was firmly frozen in place, after prying it apart I found huge burrs and a tight fit that needed serious work.

After cleaning up and deburring, and polishing of the gas seal and breach block for free movement I noticed there is .018 gap between the gas seal and breechblock “Pocket for the gas plate and got to thinking about a WAVE washer (see Pic). I found two washers almost the exact diameter and height I needed to allow the gas plate to “Float” always against the breech face with 10-12lbs pressure.

Both are made of 17-4 PH stainless steel and look promising as A solution to seal plate position to avoid gas leakage and allow good movement of breechblock without binding/drag. Shooting to see fouling issues is yet to be determined.

http://www.seastrom-mfg.com/seastrom_ma ... 5806-256-3 (http://www.seastrom-mfg.com/seastrom_manufacturing_catalog/Search/PriceDelivery.aspx?5806-256-3)
Product Number: 5806-256-3
Category: WAVE SHAPE SPRING WASHER
Material: STNLS 17-7PH


A ±.010 B ±.010 C ±.012 T THICKNESS ± 0.0020 NO. WAVES SCREW SIZE
0.645 0.795 0.040 0.012 3.000 9/16


http://www.seastrom-mfg.com/seastrom_ma ... 5806-149-3 (http://www.seastrom-mfg.com/seastrom_manufacturing_catalog/Search/PriceDelivery.aspx?5806-149-3)

Product Number: 5806-149-3
Category: WAVE SHAPE SPRING WASHER
Material: STNLS 17-7PH


A ±.010 B ±.010 C ±.012 T THICKNESS ± 0.0010 NO. WAVES SCREW SIZE
0.650 0.790 0.062 0.010 3.000 5/8


With this done I moved on to trying to find “Pedersoli Brass Cartridges” and found out they are not available in any qty at a reasonable price.

I decided to make my own out of .500” (+.000 Minus.002) Diameter X .032 (+.000 Minus.002) wall (.436” I.D.) brass tubing, I paid $42 for 24 feet, enough to make 118 tubes. I had to turn the outside to .497 diameter (slip fit into chamber) and bore one end to .460 (for 45-70 bullet) x .465 long (bearing band length on 405 grain SPG lubed bullet) and cut to length to 2.200”, next I purchased 41 magnum brass (.434 diameter x .492 rim OD) and lock tighted 15 cases and soldered 15 cases and set overall length to 2.300” which is the depth of my chamber insert. After cleanup and curing I #4 center drilled a .127 diameter hole and 60 degree chamfer to aid ignition. With newspaper over flash hole the cartridge holds exactly 52 grains of Swiss 1.5 Im thinking 1200 FPS? and maybe good out to 400 yards.

As a back up I turned a brass sleeve 2.300” long to .497 diameter and 2.300” long for loose powder shooting (holds 76 grains of loose Swiss 1.5 = 1350 FPS?) .

Next trip is to the range to see how the cartridges and gas plate work.


http://pic20.picturetrail.com:80/VOL149/8996569/19640107/327848182.jpg
http://pic20.picturetrail.com:80/VOL149 ... 848182.jpg (http://pic20.picturetrail.com:80/VOL149/8996569/19640107/327848182.jpg)

Bruce Cobb 1723V
08-03-2008, 09:38 PM
I tried some similar in a .50 cal and the cases always got stuck in the chamber and wouldn't fall out