Dirty bore stabilizes cast bullet, clean bore does not?

[David Sinko]

Yesterday I shot an IDPA match with my 625-4 .45 ACP that has a 2" barrel from a 625-10 installed. Before the match I decided I'd give the gun a good cleaning. I put a couple hundred rounds of various types of ammo through it and it hadn't been cleaned thoroughly since I got it back from the 'smith. First stage with the sparkling bore it's clear that some of the hits are out of round. The bullet is a commercial hard cast 230 gr. RN that had been shooting perfectly until now. While it's clear that some of the holes are not round, there is nothing dramatic like sideways hits. This problem continues for about three or four cylindersful and then disappears. I have never experienced anything like this before. Does anybody have an explanation for this? Does S&W use a different rifling process with some of these newer 625 barrels?

Dave Sinko

 

[Maximumbob54]

EDM rifling? Unknown alloy and lube combo? Consistent pressure in all your loads? A few bad bullets that you don't know if they were sized right? Is this all to say the bore was lined with lead when you got home???

 

[mtgianni]

Fouling shots are standard in many matches to get the gun shooting to aim, eliminating a cold barrel, ensuring that the same bullet lube is consistant throughout the bore, as well as sight picture. I can't comment on the rifiling of the 625 but grouping does change for me with a clean bbl than a fouled one. Fouled not meaning dirty just coated with the same lube that you will shoot with.

 

[Skip Sackett]

Not much help here. Never had that happen before. Since they are commercially cast, are they really hard? Can you dent them with your fingernail? How do they fit in you throats, clean and dirty? What is your load?

 

[Rule3]

Fouling shots are standard in many matches to get the gun shooting to aim, eliminating a cold barrel, ensuring that the same bullet lube is consistant throughout the bore, as well as sight picture. I can't comment on the rifiling of the 625 but grouping does change for me with a clean bbl than a fouled one. Fouled not meaning dirty just coated with the same lube that you will shoot with.

I go with this.

No wonder I can't hit anything, my guns are too clean!

 

[Maximumbob54]

Fouling shots are standard in many matches to get the gun shooting to aim, eliminating a cold barrel, ensuring that the same bullet lube is consistant throughout the bore, as well as sight picture. I can't comment on the rifiling of the 625 but grouping does change for me with a clean bbl than a fouled one. Fouled not meaning dirty just coated with the same lube that you will shoot with.

Wait, are we talking rifles or a two inch barrel revolver...

That sounds like how you describe a bench rest rifle shooting...

 

[scooter123]

I have to ask if the targets were backed up by cardboard in good condition. Last time at the range I noticed some keyholing with my hits on the paper. Looking closely at the target revealed it was just the way the paper was tearing. Put a sticker on the target to confirm my suspicion and the hits on the sticker were perfectly round. It's one issue with round nose ammo, if you shoot into an unsupported paper target you don't get nice clean holes like you do with a wadcutter.

 

[fredj338]

Have you slugged the clean bbl? It is possbile it is slightly oversize & your bullets are skidding a bit, then you get some lead build up ealry in the bbl & following bullets are being stabilized with a slight decrease in groove dia? Just a guess. Lead bulelts run best when sized to fit groove dia UNLESS the throats are larger, then try to mtch throat size. If the thorats are small, the bullets nedd to be softer & bump up on hitting the bbl grooves.

 

[venomballistics]

Ive run into related issues.
clean bore, iffy accuracy and leading.
the problem with fouling shots was that the bore got leaded a bit too.
How I solved this was with a bore mop slathered with grease.
I'd run this through to get a light coat of grease in the bore and between the next four shots. thereafter the bore was seasoned to spit heavy metal all day without a hitch.

 

[Skip Sackett]

Ive run into related issues.
clean bore, iffy accuracy and leading.
the problem with fouling shots was that the bore got leaded a bit too.
How I solved this was with a bore mop slathered with grease.
I'd run this through to get a light coat of grease in the bore and between the next four shots. thereafter the bore was seasoned to spit heavy metal all day without a hitch.

Same theory I use for my muzzleloader. T/C Encore, Hornady Sabots with their 250gr FTX. Between shots, I use a T17 seasoning patch followed by 2 dry ones, and it makes the bullets seat consistently.

Accuracy is exceptional even with open sights.

 

[David Sinko]

The ammo is good. I loaded a few thousand rounds of this stuff a while back and use it as a match load in all my 625s and Glock 21 (Bar-Sto barrel) and never had any stability problems until now with this short barrel. The targets are cardboard and not floppy. I suspect the barrel, either due to its short length (ALL my 2" barrels misbehave with something or other) or the way it was rifled. Or both?

Can leading really be beneficial? Once the bore starts to catch lead, can it reach a happy state of leading and then shoot well, if it turns out that the bore really is slightly oversize?

I guess I should slug the bore first to know the exact dimensions.

Dave Sinko

 

[venomballistics]

The ammo is good. I loaded a few thousand rounds of this stuff a while back and use it as a match load in all my 625s and Glock 21 (Bar-Sto barrel) and never had any stability problems until now with this short barrel. The targets are cardboard and not floppy. I suspect the barrel, either due to its short length (ALL my 2" barrels misbehave with something or other) or the way it was rifled. Or both?

Can leading really be beneficial? Once the bore starts to catch lead, can it reach a happy state of leading and then shoot well, if it turns out that the bore really is slightly oversize?

I guess I should slug the bore first to know the exact dimensions.

Dave Sinko

no ... leading is bad ... whats useful is that greasy sludge like fowling produced by the lube and powder.
it seems to provide a slick non stick layer and perhaps even some sealing capacity.
Since your using this load in a revolver, perhaps another observation may apply. one thing ive noticed in a 44 magnum using a load of fast burning powder in 44 specials was that the load suffered some inaccuracy and all recovered slugs were flat sided as if they skidded across the rifling rather than engage it . a slower burning powder seemed to end this, leanding to a theory that the fast rate powder had the bullet moving too fast at the time it passed through the cone ... the slow powder made its speed in the barrel after it passed the cone

 

[Fkimble]

Is this a light load? The load I use in my 4, 6 and 8 3/8 inch 38's shoots just great, but in my 38 snubby it shoots awful, 8 inch groups at 7 yards. I shoot steel so not sure about keyholing. Problem is its too slow out of the snubby. Bumped the load by .2 grains and it puts em all in one splatter mark on the steel.

 

[dla]

Yesterday I shot an IDPA match with my 625-4 .45 ACP that has a 2" barrel from a 625-10 installed. Before the match I decided I'd give the gun a good cleaning. I put a couple hundred rounds of various types of ammo through it and it hadn't been cleaned thoroughly since I got it back from the 'smith. First stage with the sparkling bore it's clear that some of the hits are out of round. The bullet is a commercial hard cast 230 gr. RN that had been shooting perfectly until now. While it's clear that some of the holes are not round, there is nothing dramatic like sideways hits. This problem continues for about three or four cylindersful and then disappears. I have never experienced anything like this before. Does anybody have an explanation for this? Does S&W use a different rifling process with some of these newer 625 barrels?

Dave Sinko

Bores season. That's why you never, ever clean a 22lr bore until the end of the season.

 

[mtgianni]

Wait, are we talking rifles or a two inch barrel revolver...

That sounds like how you describe a bench rest rifle shooting...

The principles are the same, it just takes far less shooting to coat a 2" bbl.
I believe that far more guns are ruined by over zealously cleaning them than by shooting out the mechanism's.

 

[Rule3]

Bores season. That's why you never, ever clean a 22lr bore until the end of the season.

I find that statement more "internet folk lore" than anything else.

Where is a proven scientific study proving that? Why is a 22 any different than any other ammo? The magic lube used on some bullets? Some are lead, some copper plated. So 22's don't get dirty but other calibers do??

So that statement should be true for a .223 Rem also.

Right up there with "breaking in a new rifle barrel" cleaning every shot, but it's not needed for handguns??

 

[Paul5388]

A .22 LR rifle actually never needs cleaning. Just look back at the thousands of blocks of wood the Nylon 66 shot without cleaning. In fact, for a trying experience, attempt to break a Nylon 66 down for cleaning. A .223 normally doesn't shoot lead bullets, plated or otherwise, so it's comparing apples to oranges.

 

[brucev]

I don't know if there is a problem with your load in the short barrel of your revolver. I've been shooting commercially hard cast lead bullets in my 1903 rifle for several years using a mild 8.0 gr. load of Unique. At 100 yds., it routinely produces 10 ring or smaller groups. If I clean the barrel thoroughly, the first couple of 10 shot strings will not do as well. Then the barrel settles down and starts producing its normal results with that load. As a result I've not cleaned the barrel on that rifle in over two years of use in competitive vintage military rifle matches. I just wipe it with a bore snake. Perhaps it is similar to the results you've been getting with your revolver.

 

[walnutred]

We were told not to clean our NM M14s during the shooting season. We removed and cleaned the trigger group. Wiped down the outside metal parts with a dry rag then a lightly oiled rag. Ran a rag through the mag well and that was it. The bore was left alone and the barrel/action assembly never left the stock. Of course we shot the same lot number of ammo all season as well.

The guys shooting small bore did not clean the bores and shot the same ammo as well during the entire season. The theory was that differant manufactures used differant lubes and mixing lube types was bad for accuracy.

 

[Rule3]

A .22 LR rifle actually never needs cleaning. Just look back at the thousands of blocks of wood the Nylon 66 shot without cleaning. In fact, for a trying experience, attempt to break a Nylon 66 down for cleaning. A .223 normally doesn't shoot lead bullets, plated or otherwise, so it's comparing apples to oranges.

I have several Nylon 66's. When purchased a few had so much gunk in them, it required a "putty" knife to clean. And yes I can take them apart. They worked dirty, So? The rifling in a 22 magically does not get fouled??

Yes, you can shoot thousands of rounds through them as you can any gun. The infamous Glock, XD, Berreta tests. Doesn't mean that accuracy does not suffer. I only used 223 as it is a 22 bullet.

So apples or oranges it still is no "proof" that a 22 is any different than any other caliber. Find a statistically valid test that proves a 22 need not be cleaned??

It's a firearm like any other tool, it needs to be cleaned.

This article is about Marlins but the gist is the same. It's even written in Western Wisdom

Western Wisdom: Cleaning a Marlin .22 Rimfire Rifle