Would shallow rifling contribute to lead fouling?

[bigmike13]

I did some side by side testing between my friends PT1911 and my RIA GI, using the last batch of 230gr LRN with 6.4 grains of unique behind it. I noticed that the barrel in the Taurus had little if any fouling and the RIA was smeared up pretty bad. I am wondering if the shallow rifling in the RIA is the culprit in the what variable fouled up my barrel as my bullets are .452 and I did not use the factory crimp die or crimp them heavily.

[Angus]

22LR barrels have incredibly shallow rifling and I've never had to scrape lead out of my bores. Have you slugged them both? Your barrel may be a bit oversized.

[yondering]

More likely the RIA is a little oversized, or has a rough/sharp throat (transition from chamber to rifling.)

The rifling is a possibility, but it's not the first thing I'd suspect. If you can fire a few rounds into wet newspaper or something like that, you can look at the rifling on the recovered bullets. If they are stripping the rifling, you'll be able to tell. If the shallow rifling is the problem, a harder cast bullet should help. (Still needs to be sized .001" over groove dia though.)

From your description, it sounds like you're doing things right, but the RIA may need a little attention. If the throat is sharp or rough, you can firelap it pretty easily. A few rounds at 320 grit and then a few more at 600 grit should leave it mirror smooth.

[S.R.Custom]

The RIAs have a bit rougher finish in the bore. (I've had a couple.) It smooths out after a decent break-in. My A2 doesn't fould any more than anyone else's now.

[NickSS]

My guess is a bore that needs to be broken in. You can do this with jacketed bullets by firing one or two and cleaning the bore and repeating for ten rounds then fire 10 at a time and clean. After 50 rounds or so the bore should be smooth enough so that it should stop leading. If not try a different lube. I have found that lube makes a big difference in some guns when leading is concerned. Also make sure that your bullets are not undersized for your groove diameter. depth of rifling should not make a difference.

[Bret4207]

If the barrrel itself is acceptably finished then you have a fit issue. Where to go with that is the question. Sizing and alloy are the easier places to start along with the load. All it takes is one variable to be wrong to give you leading.

[Lloyd Smale]

Shallow rifling with soft lead pushed to fast is a recipe for leading.

[Rodfac]

I'd slug the bore, find a bullet that was .002" larger, that feeds, use a moderate load and an alloy that's about 50-50 lead and ww. Generally that will do it for me. You need a slightly oversize boolit pushed hard enough to obturate in the barrel, with adequate lubrication and a moderately hard alloy to prevent leading. I'd play with the sizing first, then the charge level, then the alloy before I'd mess with anything in the barrel itself. Others here can recommend a "works 99% of the time lube mixture" to get you started, but in general, and in my experience, a softer lube is easier to make work than one of the super stiff commercial lubes. JMHO, Rodfac

[SPRINGFIELDM141972]

I have a 1928 Argentine that does the same thing as your RIA. The barrel on mine is worn out. It still rifling in the academic sense, but no matter what alloy or speed it is still going to lead up badly. I have considered replacing the barrel but have opted not to,since its an under the seat truck gun.

I would defiantly go through break in procedure prior to giving up on cast boolits or over sizing your boolits and have to be concerned with which pile of rounds go to which gun.

Regards,
Everett

[MtGun44]

"No matter what alloy or speed". . . . . . .

These are not the primary factors in leading, they are secondary factors. The primary factor is
SIZE. Have you slugged the barrel in your 1928 Argentine? If not, you need to. Highly
likely you have an oversized bore and need fat boolits.

Bill

[SPRINGFIELDM141972]

Bill

You are probably correct, the bore probably is over-sized, but I do not want to have 2 different sized 45 acp rounds kicking around. For me it is more importent that my 45s function, rather than be easy to clean. So long as accuracy is acceptable at self-defense distances. All of my 45 acp ammunition is sized to the minimum recommended lengths and diameters to ensure they will function in all of my chambers. I do have a 1911 with a tight chamber and any boolit over .453 will not allow the round to chamber. So I choose to load my ammunition to function within that chamber, and therefore function in all of my 45s.

I did not intent to steer BigMike13 away from the sizing option, I only meant to encourage him to try breaking in his barrel first.

Thank you for comment though. It made me qualify my previous statement which I should have done in the first place.

Regards,
Everett

[44man]

I agree with Lloyd. Shallow rifling is a recipe for skidding and stripping boolits. Make the boolit very hard and the proper size.

[Wayne Smith]

Stipping with a soft boolit in shallow rifling is a function of the lead not being hard enough to grab the shallow rifling, thus it strips. You may only have to harden it a little for it to grab. Changing your alloy is the easiest first step.