Needing boolit advice for new .45 Colt Rolling Block carbine

[Montanaguy]

I recently acquired a beautiful little Pedersoli rolling block carbine in .45 Colt. It appears brand new, with added front and rear sights. The Pedersoli Soule tang sight seems perfectly adequate for those 900 yard shots and the front sight has more than a dozen inserts. I don't expect to use this little guy for anything over 100 yards. Thus I removed the Soule and hope to replace it with a small tang sight. I checked with Lyman and they don't have a sight that will fit. Any suggestions and help on this would be greatly appreciated.

I made it to my range last week and fired my first handloads at 50 and 100 yards. The load was 9.0 Unique with a 200 gr. Acme cast boolit. At 50 yards it made 3-4 inch 5-shot groups. At 100 yards groups grew to 12". I shot some 225 JHP with the same load and similar results. Definitely not the results I was hoping for. My 1866 .45 Colt Uberti carbine with the same loads was making 1 1/2" -2" at 50 and 4-5" at 100 yards. I obviously plan to work with additional loads, but where to start? Heavier boolits? Hotter loads? (with 9.0 Unique cases were not obturating and I was getting leakage to the face). Your suggestions would be most welcome and appreciated.

Here are photos of the carbine. I think you'll agree it's nice!

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[marlinman93]

I always start by slugging the bore to determine what size bullets it needs. Then check twist rate to figure out how heavy a bullet to use. Until you know groove size, and twist rate you could send a lot of lead downrange and never get any accuracy. Also need to check OAL the chamber will accept, and seat your bullets where they just kiss the rifling, but chamber easily. I wouldn't bother with a chamber cast for the .45 Colt for now.
That load shows as a max load in my Hodgdon manual, so may also want to back it down a little to see if things settle down.

[Montanaguy]

I always start by slugging the bore to determine what size bullets it needs. Then check twist rate to figure out how heavy a bullet to use. Until you know groove size, and twist rate you could send a lot of lead downrange and never get any accuracy. Also need to check OAL the chamber will accept, and seat your bullets where they just kiss the rifling, but chamber easily. I wouldn't bother with a chamber cast for the .45 Colt for now.
That load shows as a max load in my Hodgdon manual, so may also want to back it down a little to see if things settle down.

Thanks, I found the twist rate to be 1/16" and will slug the barrel. I'm wondering what the 9.0 grs. of Unique smokes the brass and fails to obturate. It's fast-burning powder. Fired cases don't appear to be swollen.
I appreciate the suggestions. More winter chores!

[marlinman93]

Thanks, I found the twist rate to be 1/16" and will slug the barrel. I'm wondering what the 9.0 grs. of Unique smokes the brass and fails to obturate. It's fast-burning powder. Fired cases don't appear to be swollen.
I appreciate the suggestions. More winter chores!


That's odd? Not sure why the cases wouldn't seal in the chamber, but since they don't it may be time to do a chamber cast after all and measure it to see how big the chamber is? Might be oversized if it's not sealing.
The 1:16" twist should be fine for this cartridge, but could up the bullet weight to a 250 grain to see how those shoot?

[Tall]

I would try a slower burning powder like IMR 4227 or 2400. In a rifle barrel those powders will work well.

[Randy Bohannon]

Anneal a couple of brass pieces really well then load them up and shoot them then measure the case mouth. That will be your bullet size.

[Bigslug]

Good advice from Marlinman already.

One nice thing about a single shot: unless you are going for ammo that is interchangeable with a handgun, you can ignore the crimp groove in the bullet, use a taper crimp, and play with seating depth for optimum distance off the lands.

I'd definitely try a heavier bullet - 255 grains being kinda standard for the round.

Keep the mid range Soule sight. You might find miniature buffalo!

[Nobade]

Bigger bullets. See what is a slip fit in a fully formed fired case and that will be your target area. My 1894 Marlin likes .457" bullets to perform it's best, and is very accurate with those. Using .452" or other normal 45 Colt bullets it does what your rifle does. Since it's a single shot you may not even need to resize the cases if you keep the pressures down, they last better and seal the chamber better that way.

[Montanaguy]

Thanks for the very helpful advice, guys. I now have noticed that cases fired in the RB carbine have a slight swelling .245" up from the rim. Case diameter in front of rim is .475" and at this swelled area is .483"+. The swelling is noticeable to the eye. Cases fired in the 1866 carbine with same load same day evidence no swelling at all. I assume this means a slightly oversize chamber in the RB? I'm going to try Nobade's suggestion of not resizing cases and using .457" bullets.

Pedersoli indicates that for the carbine, lands are .445" and grooves are .453". I'll try to confirm that on my carbine.

[Harter66]

Anneal a few cases . I had a bunch that started smoking in a BlackHawk bumping up the load did nothing to help it .

What every your pistol is giving you with Unique under a 250-260 gr bullet expect 200 fps gains up to 20" at 24" speeds will be declining.

A very reputable gentleman ran numbers through a data generator, it's the well known load something one that I can't ever remember the name of, with data held to 20 kpsi a 350 gr custom over 19.0 of H322 did 1260 fps . The max load from his data was 21.3 . I would encourage you to use printed data for 255s and try those . The 1-16" twist will fix the issues I faced with the 1-32" carbines .

Definitely slug the bore , even if you only do the first and last 2" . I have 8 and a 9th coming 45 pistol barrels to load to . 3 are .451 , 3 are .452 , and the last 2 are .4500 in the grooves. 2 of the .451s won't take more than .453 the other 6 swallow .454 all day including those with the the .450 grooves . 2 of the 4 carbines have factory chambers at .496 major diameter in a tapered chamber that ends at .482 . The sloppy but equal Ruger chambers are only .484 .

The ACP chambers and 45 Raptor chambers are only .478 .

I would suggest that you slug the bore , anneal a few cases , and fire form with a standard load in the 8.5 gr of Unique with a fat cast bullet or possibly even a hollow base bullet. While it is unlikely it's possible that the RB was built with 1st generation SAA Colts dimensions for BP and in fact has a chamber approaching .490 with a .458 groove .

[.45Cole]

If that's your only .45 colt I'd polish out your sizing die or "neck" size only. 9.0gr unique is a good load, sounds like the chamber is cut too generously. I also find best results with soft lead boolits, my 1885 lw .45 colt loves 200gr SWC over unique.

[Montanaguy]

Thanks to all of your suggestions and good advice, I had a better day at the range with my .45 Colt rolling block carbine. I braved the 35 degree cold and plowed a trail into my shooting range. I had dug up some 320 grain cast gas check boolits sized .457" as well as some 300 grain JSP .457". I loaded the 320s with 14.0 grains of AA 5744 and the 300s with 8.3 grains of Unique. Velocity with the 320s was 935 fps and the 300s with Unique was 988 fps. Sights are rudimentary!

As a result, the groups shot at 50 yards shrank from the 4"-5" I got with 9.0 Unique and 200 and 225 grain cast bullets a couple of weeks ago. Here's what they looked like today. It sure seems that the much heavier boolits sized .457" versus the lighter .452" and .454" made all the difference. Thanks again for your help!

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[Nobade]

Looks like you're on the right track. The new rifle should be more enjoyable now that you have an idea of what it wants to be fed.

[barnabus]

what soule sight is that