38-55 Tight Chamber Issues

[1885_Highwall]

Hi, I’m looking for some help with an Uberti Highwall in 38-55. The barrel slugs to 0.3815 but the largest bullet I can chamber is 0.380. A .381 bullet or larger will not chamber. I have the thin-wall Starline brass and the Lee factory crimp die, as recommended by others. So far my best load has been a 255 grain (~15 BHN) boolit with 45 grains of 3F. However, I’m getting 4 to 5 inch groups at 50 yards. Starting to wonder if I shouldn’t get the chamber reamed or have to gun re-barreled.Seems like most moulds drop in the 0.376 to 0.378 range.

i just got some 40:1 to cast my next batch. Am hoping they will obturate and get better accuracy.

Any suggestions or ideas?

Thanks!

[Cast10]

Make sure the case is not swollen due to mashing that big boolit down in it. If so, you’ll need a M-die/expander.

[1885_Highwall]

Thanks, I currently have the RCBS cowboy dies that came with two expanders. One at .376" and the other at .379". I’ve been using the larger of the two. However, I’ll order an M-die and give it a shot!

[country gent]

Ink the case and see where its binding. the ink from a permanent marker will rub off and show the tight points. Then work from there.
The chamber could be polished out a couple thousandths to allow for the bigger bullet if needed.
You need to find out if its the actual case or throat binding on the bigger bullet. A chamber cast may tell a lot.
On my single shots I dont crimp just iron out any belling if any.
If the throat was cut for .375-.378 bullets then it may be the issue with .381 dia bullets. Again a chamber cast will show this.

How far from seating in the chambeer are you?

[1885_Highwall]

Thanks! I’ll try the inking trick and report back. Sounds like a chamber cast would be worthwhile too. I have the 2.080” Starline brass and when seating a bullet 0.020” off of the lands, the first grease groove is completely out of the case. I’m thinking I need the longer 2.125” brass. With the .380 bullet, I crimp the bare minimum, just until they chamber. With the .381 and larger bullets I have tried incrementally increasing the crimp and testing to see if they chamber. Ultimately, I get to maximum crimp before they fully chamber.

[Cast10]

Thanks, I currently have the RCBS cowboy dies that came with two expanders. One at .376" and the other at .379". I’ve been using the larger of the two. However, I’ll order an M-die and give it a shot!

Th .379 expander screwed down more should work. Mdie/Expander=same. I’d get some calipers and start measuring the case as compared to the SAAMI chamber drawing and/or a cast of the chamber. I’d opt for the chamber drawing. I’d do that before I went further. Polishing can improve the situation too, as previously stated. But I’d certainly measure first to know where the oversize is occurring.

[Nobade]

Don't resize the cases, bell minimally if needed, cast bullets from 1:20 or softer, use good lube, and it will shoot. Those have fast rifling twist and like heavy bullets.

[fordwannabe]

If the problem is chambering a .381 bullet in the case. Try trimming the brass a few thou and retry DON"T change the overall length just trim the brass. Keep trimming a few thou at a time until it will chamber. It wont crimp in the crimp groove but it will now chamber.

[Gtek]

A pound cast or Cerrosafe would tell you what is there and what you need to do. If it is anything like their percussion revolver math, groove is usually a few over chamber, grrrrrr! If found tight that should be an easy one to spin a chamber reamer in there and touch it up.

[Nobade]

That mismatch is intentional. It is what is on the SAAMI print. As long as you use black powder and soft lead it works just fine. My H&R target classic or whatever they called it is the same way. Useless with smokeless and hard bullets but an absolute tack driver with paper patched pure lead bullets and black powder. PTG makes a reamer specifically to open up the case mouth on these rifles so you can use hard bullets and smokeless and a lot of folks go that way but it's hard on the brass and you can't go back after doing it. That's got to be an individual's choice with their own rifle.

[Michael J. Spangler]

https://www.starlinebrass.com/articles/loading-with-correct-38-55-winchester-cases-38-55-rifle/

[Nobade]

Good article, I hadn't seen that before. It aligns with what I figured out many years ago. Just load them like they're meant to be loaded and they work great.

[mehavey]

(~15 BHN)Waaaaay too (unnecessarily :p)hard.
Go with 0.380"/30-1 (BHN 5.8) and obturate early just as the article indicates.
https://thefiringline.com/forums/showpost.php?p=6657922&postcount=1

Note: AA5744 would work just as well here, and powder coat get you additional 25-30% velocity

[Gtek]

Well, Thanks for the article, I learned a little something today!

[Calamity Jake]

Let a smith open up the throat to accept that .381 boolit.

[1885_Highwall]

Thanks for all of the insight and feedback! I plan on making a chamber cast and trying out paper patched bullets. In the mean time I did load up some 40:1 alloy 255 gr. bullets (0.380”) to test. Starline 2.080” brass and bullets seated approx 0.010” off the lands. Sitting on 3 gr. IMR-4227, 42 gr. FFFg, a 0.030” veggie wad, and a piece of news print. Lubed with SPG
327222

[Nobade]

That should work well.

[Chill Wills]

Just curious, are these Uberti's 1885 chambered for the original length of 2.125" or the short case.