Hello everyone,
I also posted this on the Cast Boolits forum and our Ask The Gunwriters forum. I have some concerns about my beautiful new 4 5/8" .32 H&R Single Six. It's an older "New Model" that I have not yet fired, just recently bought it from a member over at 24hourcampfire. He said it only had about 50 rounds through it and it looks it - it's pristine.
Thought I would try out a few different commercial cast bullets before I bought a mould for it. My first batch are the Acme bullet 100 grain FP, which looks to be about the same as the RCBS 32-98 SWC. The bullets I got from Acme are listed as 16 BHN and are powder coated. They are advertised as sized to .313", but based on a small sample most are .3133" with less than half coming in at .3130".
I loaded up 30 at the very mild listed max for the 100 grain in the Lyman book, 2.7 gr. Unique, planning to take it out for its first range trip this week.
I thought I'd better check those bullet versus the cylinder throats (yes, I did this AFTER loading up a bunch...I know...) and was surprised how extremely tight they were. It took a great deal of force to drive one through the throat, and it came out at .311. Uh-oh, time to slug the bore.
I slugged the 6-groove bore and two of the opposing grooves are right at .312 with the other one just over .3125 (how common is this - one groove slightly deeper?).
After taking all my measurements on the soft lead slug multiple times I bumped it up and then used it (instead of the 16 bhn bullet) to slug the throats and again got .311"

Everything I have read says these cylinder throats ought, ideally, to be about .313.
Questions:
1) Are there any safety concerns with a 16 bhn bullet that is at least .002-.0023 over throat diameter being fired with this load (listed at about 13K CUP in the Lyman book)
2) Is it a waste to even shoot these for accuracy? I'd like to at least get my sights set up on paper. Am I going to see a ton of leading?
3) What should I do about the throats? I fixed undersized throats on a Ruger .45 colt cylinder myself using some tricks I think I read in Ross Seyfried article probably 30 years ago but what I did then would be harder, I think on this much smaller cylinder.

Thanks in advance,
Rex

On the castboolits forum, either 2 dogs or dougguy should be able to fix it

Thanks, a respondent over on Cast Boolits recommended dougguy. Figure there's any safety issue with shooting these 30 I already loaded up? I don't think there is I've just figured I'd get some second opinions first.

Thanks,
Rex

Another endorsement for Dougguy.

He's worked on 1911 barrels for me and will do a KKM barrel for a Glock 21 as soon as it arrives from the manufacturer. I'll probably send him an Alpha Wolf barrel, too.

Interesting. What kind of work is he doing to these semi-auto barrels for you?
Thanks,
Rex

Throating in front the chamber to allow a longer OAL, in addition to angling the beginning the rifling to a more friendly angle for cast bullets, and touching up the crown.

The throating contributes to lower pressure at the velocity I want with a .45 Super with 255 grain cast bullets.

With one bullet, the Missouri Bullet Company's Pinbuster, it allows an OAL of 1.26" instead of the 1.18" typical of an unaltered throat.

First off, shoot the ammo you've already loaded--you may not need to change a thing. Given that it's a light load, the worst-case scenario is that you'd have to scrub some leading out of the bore.

If you don't get the results you want, then I'd get in touch with https://fermincgarza.com/

He reamed the throats on a New Model Blackhawk 45 Colt for me, which is now one of the most accurate handguns that I've ever owned. I think he's 2 dogs on several forums.

His work is superb, and he won't charge you if you don't need to have anything done--just shipping to get the cylinder back to you.


Okie John

okie john, I've seen the name Fermin Garza mentioned and the handle "2 dogs" but did not known they were one and the same.

Thanks for that, it's good to know.

After talking with DougGuy from Cast Boolits, there are two cylinders (this one plus a .357 Blackhawk), and six hammers (for creep reduction) in the mail to him. Looking forward to seeing the improvement.

I shot the load I mentioned in the OP and it was no better than 3-4 inches at 25 yards. No problems at all with its functioning.
Thaks to everyone - I'll follow up once the work is done.
Rex

Cylinders and hammers are back from DougGuy and installed in the guns. Cylinder throats came back perfect and the six triggers (when combined with Wolff 30 oz. return springs) are running 1.75# to 2.25# with next to no creep.
Great communications from Doug, and I can recommend his work highly.
When i get a chance to shoot the "improved" 32 H&R I'll follow up with results.

Cheers,
Rex