Accuracy problems with a Pedersoli Kentucky Pistol in .54.

[mark_fare]

Hello everyone. I recently purchased a Pedersoli Kentucky pistol in .54 flintlock. This gun had alot of problems out of the box. It had a trigger pull that would tax a WWF wrestler. The main spring and the frizzen spring were so strong that it would just batter the flints to pieces. 5, maybe 10 shots out of a flint. Every time I pulled the trigger there would literally be flint shards laying all over the lock. I lightened both the frizzen spring and mainspring and lightened and re-bent the sear spring. I stoned the tumbler and sear and adjusted the sear angle and engagement and now the gun has a nice, 5lb. trigger pull with no creep. I ordered a Treso Ampco touchhole liner and modified that and now the gun goes off real well and consistently. In spite of all this work to a brand new gun, I still have a hard time getting the gun to group consistently from the bench. I use a Speer .530" swaged round ball and I started with .015" patching lubed w/ Wonder Lube 1000. I've also tried .012" and .010". I started with 30grs. 3f and have worked down in 5gr increments to 20 and up to 50. I just can't seem to get the gun to group smaller than 4" @ 25 yrds. I got the best results with a .012" patch and 45 grns. 3f.

Now in the past with other guns it has only been a matter of getting a good, smooth trigger pull and then slight experimentation with patches and charge size to dial the groups in. But with this Pedersoli all that has only produced the aforementioned mediocre results. I have started to dig deeper and today pin gaged the bore. And then measured the rifling depth. A size .542" pin goes in the bore, and the groove depth is a remarkably, (to me at least), shallow .0045".

Now when I've used a .015" patch and a .530" ball in this barrel, that is in reality .002" over size with shallow rifling, it is a real snug fit. It is hard to start the ball in the muzzle with my short starter and I can barely seat the ball all the way with a pistol loading rod. And with this tight set up, accuracy is maybe 5".

Since this is the first time I have ever run into this problem, could anybody shed some light on it for me?

 

[DanChamberlain]

If the rifling is exceptionally shallow, you probably need to go with a thinner patch and thicker ball. .535/.010?

Dan

 

[PaulN/KS]

My Pedersoli also had the trigger pull from H##l.I stoned the sear surfaces and also noticed that the trigger curl would hit the guard so bent that forward a bit for clearance.Still a pretty hard trigger.How did you lighten the springs?

 

[mark_fare]

I lightened then by filing the flat surfaces. I have a link on my home computer that shows how to do it. But alas I am at work so I will post it this evening.

 

[PaulN/KS]

Thanks Mark.I shall look forward to learning how to do this.(shhhh,I'm at work too... :winking: )

 

[mark_fare]

Thank you for your suggestion. I was thinking along those lines myself. Is there some kind of relationship between rifling depth and patch thickness?

 

For all practical purpouses you have a smoothbore. 4"@25 is not bad for a smoothie either.

Theoretically, you should go to a bore sized ball, thin patch and light load to prevent stripping the rifling and losing your spin.

The guys shooting shallow grove rifles have the same problem. When they up their charges with a normal patch ball combo they strip the rifling and get worse accuracy than a smoothbore.

 

[mark_fare]

Hi, I appreciate your input. There is one thing I might not have been too clear about in my initial post. I stated that the groove depth was .0045". That is per side. So the land dia. is .542" and the groove dia is .551" Does this still qualify it as a smoothie?!! Besides, I thought a smoothie had something to do with a lack of body hair!!!!!

 

[DanChamberlain]

The shallower your rifling, the thinner your patch should be...I think that's how it goes! You might actually find a conical like a mini to work best for accuracy as it has a skirt that would flare to engage the rifling.

Dan

 

[mark_fare]

Paul, here is the link on how to lighten v-type mainsprings.[url] http://blackpowderonline.com/MAY03RdcngActnVTypMnsprng.htm.[/url]

Mark Fare

 

[renovato]

Mark, as suggested, a larger ball and thinner patch might be a solution. If you go to a thinner patch and still have the problem, try a felt wad underneath it. Wads help protect the patch and they've increased the accuracy in every gun I've tried them with. In fact, you might try them with the ball/patch combo you're using now, especially if you're having any problems with blown patches.

 

[jdixon]

Hello everyone. I recently purchased a Pedersoli Kentucky pistol in .54 flintlock. I still have a hard time getting the gun to group consistently from the bench. I use a Speer .530" swaged round ball and I started with .015" patching lubed w/ Wonder Lube 1000. I've also tried .012" and .010". I started with 30grs. 3f and have worked down in 5gr increments to 20 and up to 50. I just can't seem to get the gun to group smaller than 4" @ 25 yrds. I got the best results with a .012" patch and 45 grns. 3f.

Since this is the first time I have ever run into this problem, could anybody shed some light on it for me?

I have a Pedersoli catalog here, a couple of years old but I think this information is correct. The Kentucky Pistol in .54, model # S313 has a 12" barrel, 7 lands and grooves and a 1:23 twist. They call for a .535 round ball, you said you were using a .530. Can't believe that the larger ball would do everything you want, but it might be worth a try. You are probably right on with the 30 - 45 grain charge of 3F for target work.

You mentioned something that caught my eye. You were having trouble getting the ball seated on the powder charge. If you are not consistently seating the ball that will screw up your accuracy down range a bunch, may want to try using a small light mallet to start and seat the balls. I find that tapping the ball down with a mallet is easier on both you and the gun and you get a consistent seating every time. Another must that I didn't see you mention, swab between each shot.

What Plink mentioned about patch condition is important, his suggestion about a felt wad is another alway try when accuracy is a problem, especially if the gun is abusing the patches.

I put up a post a few weeks back on a similar Pedersoli pistol. That post may have some information that will help - see [url] http://www.muzzleloadingforum.com/fusionbb/showtopic.php?tid/202409/post/new/#NEW[/url]
There are several photos and targets shot all the way out to 100 yrds. The barrel on that gun is only 4 1/2" longer than yours. You should be getting results similar to what is shown there. Keep working on it and asking questions - you'll figure it out.

 

[mark_fare]

Thank you for your response JR. I went and looked at the Pedersoli website and like you said, they recommended a .535" ball. The literature that I got with the gun was very generalized, and applied to all of their weapons. In the literature, they recommended a .530" ball and a .015" patch for .54 weapons, while their website recommends a .535" ball. I have a .54 Pedersoli Rocky Mtn. Hawken, and it shoots excellently with a .530" ball and .018" patch over 120 grns. of 2F, and it is not difficult to load.I assumed that the same size ball would be a good place to start in their .54 pistol. After I tried with the .015" patches, and experienced alot of difficulty ramming the ball down the barrel, there was no way I was going to try with an .018" pillow ticking patch!

There are some differences between the .54 and the.50 Pedersoli kentucky pistols. The .50 has 12 grooves and a twist rate of 1:18. The .54 has 7 grooves, and a twist rate of 1:23. So the barrel configuration is different between the two calibers. I'd sure like to know what the land and groove diameters of your .50 pistol barrel are.

By the way, I was so impressed with your report on the Ky Bounty Hunter you built, that I found that I could order one through Thunder Ridge, which I have done. I'll let you all know how it goes after I finish the kit.

 

[jdixon]

Yeah, there are some differences in the barrels but, I have to believe what you got could do better than what you are getting right now. As near as I can tell, the groove depth on the Kentucky Bounty .50 barrel is .0065. Now this was done with digital calipers, not the most accurate instrument for making this measurement. It does seem that this depth does fall into the correct range however. Some Pedersoli pistols, like their LePage target gun are very deep, cut to .011, this one is not that deep I am certain. I know most Green Mtn. barrels run a .009 groove depth, a black powder cartridge gun typically around .004 and a cap and ball revolver could be as shallow as .001. If you have an accurate instrument to measure that groove depth and it is only coming out at .0045, you may have a bum barrel. Never heard of a Pedersoli bum barrel but, it could happen. Maybe a call to some place that deals in Pedersoli's product line, like Cherry's in N.C. or Flintlocks Etc. in Mass. would get you some answers on what the correct depth for that barrel should be.

 

[mark_fare]

I used several methods to measure the groove depth. Since there is an odd number of grooves in my barrel it was somewhat more problematic. I used a test indicator as one method, small spring loaded inside calipers measured over with a micrometer as another method; ( I was measuring from top of groove to bottom of groove). Then I had our Q/A dept stand the barrel up and measure it all with our CMM, (Coordinate Measuring Machine), which confirmed my measurements. The fact that your barrel measures .0065" groove depth is actually encouraging to me. I'm going to try this weekend a .535 ball and a .010 patch and see from there. Thanks for your input!

 

[jdixon]

Yeah, I'd say you got the measurements down right. Wish I had access to that type of equipment! When you go down to the .010 patch, I would try it with felt wads. Likely to blow and burn up patches that thin, even in a 12" barrel. Something else came to mind, have you checked the crown to ensure it is not buggered in some way?

 

[PaulN/KS]

Thanks for the link.Lot of good info in this thread... :thumbsup:

 

[mark_fare]

The crown was one of the first things I checked when I received the pistol. SOP for any new gun. It is immaculate. The wads you refer to, are they the type used in C & B pistols? Do they make them in a .54 caliber?

 

[jdixon]

Yes, the thick felt wads are what I was thinking of - they come in .54 - one source is October Country - see -[url] http://www.octobercountry.com/products3.php?productid=210[/url]

 

[mark_fare]

Well I got some .535 balls and some .010 patches so after a weekend at the range I'll let you all know how things went.