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I have been trying to tune a new Pedresoli long range express rifle for the past while but no matter what I experiment with I CANNOT get 2nd shot accuracy.I am using Lymans 457125 mold backed with 110gr of Pyrodex RS ,velocities are averaging 1309fps I also have cast my bullets in pure lead/20% tin, 3.6% antimony 5%tin alloy,and,Lyman #2 all of the above blends done for me at an ISO9000 refinery no fooling around.I've adjusted seating depths,I've loaded over fiber wads and plastic and no wads.The bore of the rifle has a groove dia. of .456 and a bore dia. of 450,I've swaged bullets from .459/.460 down to .457 and .458 and ive shot bullets as cast in the 3.6 % alloy at .4585 average dia.All produce uncanny first round clean bore accuracy in the 1.25" to 1.75" range at 90m BUT the 2nd shot invariably is a fullblown keyhole,run a brush and a patch through the bore and bingo dead on ----any suggestions
 

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What lube are you using? I have a Browning BPCR in 45-70 that has gone 60 sho5ts without a significant change in accuracy. The lube must keep the fouling soft. Also a blow tube to put some moisture into the bore helps. SPG is a good commercial lube.
 

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Bigfoot said:
What lube are you using? I have a Browning BPCR in 45-70 that has gone 60 sho5ts without a significant change in accuracy. The lube must keep the fouling soft. Also a blow tube to put some moisture into the bore helps. SPG is a good commercial lube.
I am using SPG lube and the fouling seems to be not at all hard.
 

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Bigfoot said:
What lube are you using? I have a Browning BPCR in 45-70 that has gone 60 sho5ts without a significant change in accuracy. The lube must keep the fouling soft. Also a blow tube to put some moisture into the bore helps. SPG is a good commercial lube.
I have to tell you that we are talking wild inaccuracy when I say keyhole---almost like the bullet is being fired smoothbore.Do you think the pyrodex in such a capacity could present the problem as far as fouling --I've used it in every muzzleloader I've owned from 36 cal to 58 with no problems but never in such a large load.
 

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Hi, Bob:
I'm not a BPCR shooter, so I'm just speculating. First, is that pure lead/20% tin mix correct or do you mean the traditional 20:1 lead tin? If it's 20% tin it's way too hard and your others are pretty hard too.

Now if your first shot is good but your 2nd keyholes, it's most likely that the bullet is getting a good enough grip on the rifling to spin up, but skidding if there's the least bit of fouling. A difference of .006" between bore and groove is pretty shallow. It's not unusual for black powder barrels to have grooves twice that deep. It wouldn't take much fouling to fill up those shallow grooves.

Have you tried real black powder? As Marshall notes in this thread, Pyrodex doesn't give the bullet a hard swat and you may not be getting enough obturation.
http://shootersforum.com/showthread.htm?t=5939

SPG has a good reputation, but it may not be the best for your barrel. Have you tried others? I don't know how good it is with Pyrodex. I shoot a flinter and used Pyrodex just long enough to learn it's not made for flintlocks.

Is your barrel uniform in diameter, or do you have a tight spot?

Bye
Jack
 

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Hi Jack--yah I meant 20:1 haha.Anyway ,I agree with you regarding the lack of contact with the rifling on mysecond shot although if I'm not mistaken 6 thou. is not uncommon as a bore/ groove cut depth what my problem more than likely is ,is my use of Pyrodex in this case.I have changed and controlled every component except the powder.Marshalls thread reply makes alot of sense and after reassessing the loading data the slow burn of the Pyrodex loads would show greater pressures while velocities would remain fairly consistant with the blackpowder loads having lower pressuresand more bang so to speak -----I'll give the ff a try tomorrow ---thanks Jack
 

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Jack I have to say that Marshall Stanton was spot on regarding the use of black powder rather than Pyrodex.I had great success today.I fired a string of 12 rounds without any problem and as matter of fact after resighting for 100m a 5 round string produced a 1.7 x 2.5 group on target and in the black------------thank you for your direction
 

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BobLavigne said:
Jack I have to say that Marshall Stanton was spot on regarding the use of black powder rather than Pyrodex.I had great success today.I fired a string of 12 rounds without any problem and as matter of fact after resighting for 100m a 5 round string produced a 1.7 x 2.5 group on target and in the black------------thank you for your direction
I was going to add my $.02 as well. I have a Pedersoli Sharps in 45-90. I can get a 5 shot string inside of 1.5 inches using any of the following loads:

75.0 grs of GOEX Ctg., .030 fiber wad, Federal 215 mag primer, SPG lube and Lyman Postel bullet cast 25-1 and run through a RCBS.459 size/lube die. I seat the bullets out until they touch the rifeling. I also use a blow tube between shots and I weigh each charge and drop them SLOOOOOOWLY through a 24"drop tube.

32.0 grns of Accurate 5744, no card wad, same bullet, lube and seating depth. CCI 250 primer

50 grs. (by volume only) of Tripple 7, no drop tube and no compression of the powder charge, .030 fiber wad, same bullet and lube, same seating depth. Federal 215 primer.

All of my cases are extruded from RP 45-70 cases and trimmed to 2.4"

I neck size only and then expand just enough to permit the bullet to enter the case.

Any of these loads will shoot MOA at 100 yards. However, only the BP load has been tested out to 400 yards. It shoots between 5 and 7 inches at that distance from a solid rest using a Pedersoli Soule sight in the back and the covered front sight with the small circle insert.

I hope this helps
 
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