Shooting cast in pitted bore

[TinCan Assassin]

I have 2 Mosins, a 91/30 with a beautiful bore and an M44 with pitted grooves and shiny lands. Can I shoot cast in that M44 without problems? Accuracy with milsurp is shotgun patterns at 100 yds, I hope to improve that. Maybe she's just a wall hanger. Any advice would be appreciated.

[Rico1950]

I have a M98, 8mm with a mildly pitted bore. It shoots the Lee Karabiner fine.
Try it, just remember fit is KING!

[Ben]

When moving from jacketed bullet use in your Mosins over to cast requires the TOTAL removal of all copper deposits which can often take days to accomplish properly. To try cast without the removal of the copper will most likely not net you much in the accuracy dept.

Ben

[303Guy]

You might want to try fire-lapping to remove the sharp edges of the rust pits. Be careful how you do it. Properly done it will likely restore youre rifle to fine accuracy. Something to check is the condition of the crown. If not sharp and on bore size, you might have no chance but cast seems to be a little more forgiving of a less than optimum crown. Not sure though.

[Nobade]

My 91/30 has a well pitted bore, likely from being test fired at the arsenal and then not being cleaned afterward. I couldn't get it to shoot anything well until I tried using Cream 'O' Wheat filler. With 7383 powder, COW on top, and a SAECO 305 it now shoots better than I can see. I had tried jacketed bullets, cast with gaschecks, and paper patch with no joy until I tried filler. Now it is quite a useful rifle and a lot of fun to play with.

[rhbrink]

All the above is great advice I have a 91/30 like most had a very neglected bore looks like the inside of a corn cob. Did all the above and shoots OK, but one more step I used some of Bullshops bullplate and carefully wiped the bore down and shot some Saeco 305s well lubed up with LBT and believed or not it shoots a whole bunch better. I had to cut this barel back to 18.5 inches just to get to some decent rifling and even with the military sights can manage 2-3 inch groups at 100 yards on a good day when I can see the sights (some days are better than others). The key here is boolit fit and I'm not pushing it very fast about 1600fps.

Good luck, Richard

[Three44s]

+1 303 Guy!

I'd also opt for a consideration of fire lapping.

First, I'd get the book that Beartooth Bullets sells on boolit fitament! It does a very good job on fire lapping as well as an integrated approach to shooting cast.

Three 44s

[JeffinNZ]

I had a Mod 92 .32-20 lever gun the barrel on which looked like a dry river bed. Fed the right combination it SHOT!. I can be done.

[Rico1950]

Before going to fire lapping, why not try JB bore paste. A lot less abrasive.

[303Guy]

Before going to fire lapping, why not try JB bore paste. A lot less abrasive. Those would be my first thoughts. However, if the bore is rough from pitting the trick is to cut the sharp edges away with one or two fire-lapping shots using fine valve grinding paste then moving on to less abrasive compounds. In short, the less abrasive compounds don't do much (which is what we need when polishing a bore). My 'rust textured' bore two-groove only became serviceable after more aggressive compounds and application was used. There may have been more than just rust damage there - like a longitudinal burr from manufacture. It now shoots scary accurate with lubed bullets (no spelling mistake there - it sucks with lead or paper!)

You know I still don't know exactly what Cream 'O' Wheat is! Can someone please eggsplain it to mere 'down-underer' please?

[Nobade]

How about this?

http://en.wikipedia.org/wiki/Cream_of_Wheat

I get the generic kind from the Mexican grocery store, but it's pretty much the same thing.

[Bret4207]

FWIW- I have swabbed the pitted bore of a rifle with Lee's Mule Snot and let it dry. Rana dry patch through and shot much better groups with a lot less leading. It wears off though. My theory is it fills the pits.

[leadman]

303 Guy, Cream of Wheat is a dry cereal that is cooked before eating. I use it for fireforming cases without a bullet. Light charge of fast powder, fill case with COW, melt wax in the case mouth to hold in contents.

[303Guy]

Thanks for that. OK, now I know what it is. I have a snippet about wheat bran which does not have any starch in. It too can cake and be left in the case even though the boolit hits the target just fine. It is more fibrous and cushions well and seems to clean the bore. But when caked it leaves a lot of debris in the bore. Plus I had leading, possibly from a subsequent warmer load. It seems to stop paper patches from coming off the bases of PPCB's. Higher load levels with less wheat bran seem to to be good though.

[Multigunner]

My 'rust textured' bore two-groove only became serviceable after more aggressive compounds and application was used. There may have been more than just rust damage there - like a longitudinal burr from manufacture. It now shoots scary accurate with lubed bullets (no spelling mistake there - it sucks with lead or paper!)




My Savage two groove had a dense cluster of pitting midway of the bore and scattered pitting to the muzzle, all on the broad lands none noticable in the grooves.
Since figured the groove depth was already as deep as advisable, though I've found its on the tight side for these at .314, I decided to polished the lands only rather than lead lapp.

I made a thin tough leather patch with the edges forming wings to ride in the grooves. Wetting the leather and running this patch tied down tight to a 7mm jag squeezed it into the proper shape.
I then first cut a thin strip of 1,000 grit silicon carbide paper and afixed it the the patch so it would only touch the center of each land. A few passes with this began the process.
I then used strips of cloth soaked in a paste of "Steel Chalk" very fine polishing compound given to me by a custom auto parts dealer. I've used this compound to put a mirror finish on knife blades. I suspect this is an aluminum oxide compound, but only know it by its common name.

The wings riding the grooves kept the polishing action in line with the twist of the lands. The polishing strips remained centered on the surface of the lands so they didn't wear any steel away at the edges.

Theres no measurable difference in the minor diameter, only a few tenths of a thousandth at most was removed.

I had way too much time on my hands so I proceeded very carefully. I made sure there was a very slight taper to the bore with no drag or loose spots.
The rifle now shoots sub MOA with taylored hand loads and is easy to clean, with only a couple of copper streaks showing against mirror bright steel after shooting, due to a few pits that were larger than the rest. It was not worth removing any more of the land surface to eliminate those last few.

[Shiloh]

Before going to fire lapping, why not try JB bore paste. A lot less abrasive.

You bet.

One can always go to fire lapping, but this may be just the ticket you need.

Shiloh