More leading yet better accuracy?

D

dyl

New member
Here's what happened. I have an out-of-production 9mm that has terrible accuracy with 125 grn LRN Hardcast with the H&R profile (a raised band around the body of the bullet) but when it shot the bore was clean. Bullets had 1 band of hard yellow lube. Special Cleanup only involved picking away some wax/lube buildup under the extractor. Bullet size was .356 and my group size on paper would be 10 inches at 5 yards.

A couple weeks ago I tried a bullet from another company which used a messy blue lube. Same weight. Same hardness. Same diameter. Bullet shape however was a simple LRN, no shoulder or elevated band around the middle. Accuracy is much better, max group size is 4 inches at 5 yards. When I look down the bore, there are shiny lead slivers left inside.

I thought more leading typically indicated something was wrong and was associated with worse accuracy, not better.

What's going on here? Ideas?

Gun is a Bernardelli p-018 with round count <1000, bore not pitted, tight lockup, good slide to frame fit.
 
M

m&p45acp10+1

New member
Under sized bullets sounds like the problem to me.

What did the barrel slug at? Bullets should be over size. A lot of people load lighter bullets for .357 Mag/.38 Spcl. in 9 mm to get proper fit of bullets.

Fit trumps hardness by a wide margin when shooting lead.
 
M

mikld

New member
I agree with M&P. In my new FMK 9mm I shoot Lee 125 gr. RNFP sized to .357". anything smaller (even by .001") will lead. Light leading isn't necessarily detrimental to accuracy, although after a bunch of shooting and lead build-up, it can affect accuracy.
 
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noylj

New member
A little leading does not destroy accuracy. It is the accumulation of leading that will destroy accuracy.
9x19 barrels are "in spec" with a groove diameter of 0.354-0.362". Unless your barrel has a groove diameter of 0.355" or less, then 0.356" bullets are almost certainly too small.
Get some Lee Liquid Alox and lightly tumble lube the bullets. This helps me minimize or eliminate leading with bullets that are slightly too small.
Go to Penn Bullets or other source that can size the bullets to your barrel.
 
E

Edward429451

Moderator
I think you just got lucky with the accuracy and the leading is coincidental. Your gun seems to like that bullet so what you should do is try to get the same bullet, but sized .001 or .002 fatter. Your leading would go away and it might even reward you with a touch more accuracy than before.
 
D

dyl

New member
I pounded a .356 bullet through (no barrels were harmed) and it came out to .355

So it looks like the barrel is .355 at some point.

I have some 125 grn .38 bullets in .357 or .358 (I have to look at the box, it's been a while) that I considered using but tossed that idea after slugging the barrel. Plus with a Brinell hardness of 18 I didn't know if it would be too much pressure to go .003 over

Thanks for sharing your expertise. This may just be the first time I'm seeing leading PERIOD as all my other purchased 38's, 40 cal and 9mm Hardcast bullets left nothing in the bore except a bit of wax. Could be the cheaper lube.
 
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M

m&p45acp10+1

New member
Sometimes softer bullets will help. They seem to get better obturation early on. I have not used cast in any of my 9mm guns yet. I shoot a lot of .38 spcl, .45 auto, .41 Mag. with home cast bullets. All of my bullets are straight wheel weight alloy. BHN on those is guestimated to be somewhere in the area of about 10 or so.

If it is a lube problem then it tends to show lead neat the muzzle. If it is fit it starts closer to the chamber, and tends to follow the rifling.
 
R

rodfac

New member
Dyl...in your original post, did you mean 50 yds or 5 yards. A group of 4" at 5 yds is abysmal. From a rest, you ought to be getting ragged holes at that shorter distance, and most any bullet should do it and from most any type of gun...

For cast bullets in general, you need a bullet that's about .001" over groove diameter. If your barrel in .355, then a .356 bullet should work well in it, providing there are no other issues. I should note that, in loading for 9mm, I've never had the accuracy from cast bullets that I can expect from jacketed ones....and only in 9mm. In .40 S&W, .41 Mag., both of the .44's, and both of the .45's, cast bullets are usually more accurate than their jacketed brethren.

Another thought: I've had good luck eliminating leading in 9mm (and some other calibers as well) by re-lubing commercially cast 9mm bullets with Lee Liquid Alox using the butter tub, swirl method...I thin the LLA by 20% or so, then swirl the bullets...a little LLA goes a long way, then dump them out on wax paper to dry. They're a little messy to load with and handle, but the results have been terrific, cutting group size, at 25 yds, in half.

Good point, M&P,
If it is a lube problem then it tends to show lead neat the muzzle. If it is fit it starts closer to the chamber, and tends to follow the rifling.
Click to expand...

Best Regards, Rod
 
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D

dyl

New member
You heard me right

Yes you heard me right.

With the bullets the gun doesn't like: slow fire, two hand grip, whether makeshift bench rest or not, groups were about the width of a sheet of paper at 5-7 yards. I say 5-7 because it's the minimal distance of the outdoor range and I don't remember if it is 5 or 7 yards away. Yes those are horrible groups and very frustrating to think that you are far better than your equipment.

In contrast, after I get warmed up I can usually shoot out a 2-something inch hole offhand with a 2 hand grip with my M&P40c slow fire at the same distance.

The newer batch of bullets that seem to work were not shot from a bench since I was not expecting anything out of them. I had actually purchased them so I could teach a new shooter to shoot cheaply and part way through the range trip I acted on a little hope the new bullets would do better. I was pleasantly surprised. The groups were not quite slow fire, two handed, standing.

I almost feel like a smoothebore would do better than those bullets my gun doesn't like.
 
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noylj

New member
Why do people think that a bullet a few thousandths of an inch larger will increase pressure by some huge amount?
History lesson:
I bought a Browning Hi-Power in 1973. At that time, I couldn't find any 0.355" bullets and the only 0.356" bullets were 130gn FMJ-RN for .38 Super (S&W had just come out with their M39 and that was the ONLY US 9x19. I, like ALL reloaders for 9x19 at the time, used 0.357" jacketed bullets and 0.358" lead bullets and everything was fine. No noticeable increase in pressure and fine functioning. For jacketed bullets, my favorite were 125gn 0.357" JHP or JSP. Both had little to no jacket over the bullet ogive and I had to polish the rough feed ramp on the BHP.
All my 9x19s perform great with 0.357" jacketed and 0.358" lead to this day. I am shooting 0.356" JHPs nowadays from Zero.
 
D

dyl

New member
By "people" you mean me? I have heard of a diameter .001 or .002 larger than bore but have not read articles or posts or reloading manuals promoting .003 oversize. So how much DOES it raise pressure by? If I could measure it I would and deem it safe if it was. I can't so I'm cautious. I also don't know a lot of Firearm history so I can't reason that back in the day they used to <insert anything> and not many died of it.

It is good to know someone has tried .003 larger than bore with good results though. I will probably save those for my revolvers... Unless accuracy is spectacular in the 9mm.
 
B

Brian Pfleuger

Moderator Emeritus
Oversized bullets don't necessarily raise pressure all that much. There have been several reports of folks using .357 jacketed bullets in 357sig (spec is .355) with no trouble whatsoever.
 
G

GP100man

New member
Smeared lead is undersized gas cut bullets .

Slivers is bullet correct size or at least obtrurating but not strong enuff to hold to the rifling .

Try backing off a 1/10 or 2 & see what happens .

Even a bit slower powder mite do it .
 
G

Gerry

New member
An oversized bullet can result in higher pressures. This happens when it chambers very tightly because of its diameter and the case cannot expand easily to release the bullet. Such a round will be short enough in OAL, but still get get stuck in the chamber to the point where you will have to pry it out if you don't fire it.

This has nothing to do with shooting bigger lead through a smaller barrel. The shooting will swag several thousandths easily, even with Lyman #2 alloy. Peak pressures may be slightly higher, but the friction of lead against the rifling is why you need less powder for lead than you do jacketed rounds.

Basically if you can chamber it, you can shoot it. noylj has this right. Speaking of which, I've never had trouble shooting any .358" boolits through any of my 9mm guns and they all chamber well, from CZ to Ruger SR9. Just follow the most conservative starting loads of the reloading manuals you own for lead, and ideally use a chrono if you can.
 
D

dyl

New member
Hm. Well I AM using bullseye, maybe that's too fast. I like the economy of it though. I have a little unique left that I could try along with backing down the charge and trying the .358 bullets.

Thanks, will give it a go for the next range trip.
 
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