How much is one thousandth (.001 between 9mm and 38 spcl bullets)?

Cuz

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I'm asking specifically about Berry's Plated Pistol Bullets. I currently shoot their 9mm 124gr RN-DS bullets in my Glock pistol. Berry's website says they are .356 diameter. I also shoot Berry's 158gr RN 38/357 bullets in my S&W revolver. Berry's website says they are .357 diameter. Can I just load my .356 diameter 9mm bullets in my 38 special cases and use them in the revolver? Will it really make that much difference for shooting steel at local plate matches? The targets are relatively big and close. Will accuracy suffer much? Is there any danger to doing this? Will it be too hard to make a 130 Power Factor?

Any advice is greatly appreciated.

-Cuz.
 
I have heard many shooters use 9mm bullets in 38spl. If you are not shooting for pure accuracy you should be fine, and with plated or FMJ bullets you will reduce chances of extra leading...
 
This can be done if you keep the velocity down. If you drive the undersized bullets too fast they won't pick up a spin from the rifling and accuracy will suffer.
 
This can be done if you keep the velocity down. If you drive the undersized bullets too fast they won't pick up a spin from the rifling and accuracy will suffer.

Do you really think the .001 diameter size difference will matter that much?
 
Do you really think the .001 diameter size difference will matter that much?

+1

.001 is really small. Go caliper ten random bullets of the same caliber and i will give you 20$ if all are the same size down to one thousandth of an inch.
 
This can be done if you keep the velocity down. If you drive the undersized bullets too fast they won't pick up a spin from the rifling and accuracy will suffer.
The accuracy might suffer, but I'm not certain that this is the reason why.

The bore (.357 in this case) is the groove diameter. The lands stand up off the bore by much more than 0.001". As a result, a bullet only 0.001" smaller than the bore is always going to get spin.

The problem with undersized bullets is that the small space between the edge of the bullet and the grooves allows gas blow-by which can cut even a jacketed bullet. This makes the rounds inaccurate. I've seen it when I was able to recover the bullets from some rounds I shot after a fresh snowfall. The undersized bullets were a mess - they looked pitted.

Contrary to conventional wisdom, the problem seems to be worse with lightly loaded rounds because there's not enough initial force to cause the bullet to obdurate and fill the grooves.
 
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.001" is a very small increment! the thickness of a single post-it note is .004", so now divide that by 4.
 
Avid followers of Ken Waters will recall that on numerous occasions he has found small increments of slug undersize have had drastic effects on bullet accuracy -- for precisely the reasons described by Brother Coyle.
 
The accuracy might suffer, but I'm not certain that this is the reason why.

The bore (.357 in this case) is the groove diameter. The lands stand up off the bore by much more than 0.001". As a result, a bullet only 0.001" smaller than the bore is always going to get spin.

The problem with undersized bullets is that the small space between the edge of the bullet and the grooves allows gas blow-by which can cut even a jacketed bullet. This makes the rounds inaccurate. I've seen it when I was able to recover the bullets from some rounds I shot after a fresh snowfall. The undersized bullets were a mess - they looked pitted.

Contrary to conventional wisdom, the problem seems to be worse with lightly loaded rounds because there's not enough initial force to cause the bullet to obdurate and fill the grooves.

So what do think the end result will be? Decreased accuracy? If I can maintain a 2 or 3 inch group at 25 yds that should be fine. Decreased velocity? I can always bump up the load, there's plenty of room in a .38 spcl case for more powder, I'm thinking Bullseye or Tite-Group powder. My biggest concern is if it's dangerous. Can anyone confirm if there is any risk to shooter or gun???

Thanks,
-Cuz.
 
+1

.001 is really small. Go caliper ten random bullets of the same caliber and i will give you 20$ if all are the same size down to one thousandth of an inch.



for the hell of it, i just checked a few of my cast boolits (sized by a buddy of mine via a Star Lubrisizer...), .45acp, all sized to exactly .452

they're punched through a hardened steel collet. unless that steel collet is changing sizes by itself, it never gets any smaller.
 
So what do think the end result will be? Decreased accuracy? If I can maintain a 2 or 3 inch group at 25 yds that should be fine. Decreased velocity? I can always bump up the load, there's plenty of room in a .38 spcl case for more powder, I'm thinking Bullseye or Tite-Group powder. My biggest concern is if it's dangerous. Can anyone confirm if there is any risk to shooter or gun???

Thanks,
-Cuz.

2-3" @ 25 yards is exceptional accuracy for a handgun (assuming you aren't shooting from a ransom rest). i dont see that kind of grouping happening with undersized bullets.
 
Do you really think the .001 diameter size difference will matter that much?

.001 can make a huge difference. I tried some hard cast 130 gr bullets at .356 (industry standard) in a Glock 17 9mm at 1000 fps. The results were horrible with key holing and a huge group at 25 yds. The same load with .357 diameter bullets yielded a four inch group, offhand at 50yds. If the bullet doesn't match barrel diameter, accuracy will suffer and increased velocity will aggravate the problem. The bullet must engage the rifling to pick up its stabilizing spin.
 
So what do think the end result will be? Decreased accuracy? If I can maintain a 2 or 3 inch group at 25 yds that should be fine. Decreased velocity? I can always bump up the load, there's plenty of room in a .38 spcl case for more powder, I'm thinking Bullseye or Tite-Group powder. My biggest concern is if it's dangerous. Can anyone confirm if there is any risk to shooter or gun???

Thanks,
-Cuz.

It's probably not dangerous. As far as accuracy goes, I couldn't hold 2"-3" groups at 25 yards with undersized bullets (not even close) - although YMMV.

If you shoot undersized bullets, take a look at your barrel when you're done. It will be badly fouled with either lead or copper - whatever is on the outside of your bullets. After cleaning it, my guess is that you'll just use the right size from then on.
 
.001 can make a huge difference. I tried some hard cast 130 gr bullets at .356 (industry standard) in a Glock 17 9mm at 1000 fps. The results were horrible with key holing and a huge group at 25 yds. The same load with .357 diameter bullets yielded a four inch group, offhand at 50yds. If the bullet doesn't match barrel diameter, accuracy will suffer and increased velocity will aggravate the problem. The bullet must engage the rifling to pick up its stabilizing spin.

Glocks never shoot lead cast well. Something with the type of rifling they use.

I load lots of .355 90 gr jacketed bullets for use in 9mm. The .355 is basically a .380 bullet but it works fine in all my 9mms which are .356. I load it hot with a compressed powder load and heavy crimp. Accuracy is excellent.
 
Glocks never shoot lead cast well. Something with the type of rifling they use.

I load lots of .355 90 gr jacketed bullets for use in 9mm. The .355 is basically a .380 bullet but it works fine in all my 9mms which are .356. I load it hot with a compressed powder load and heavy crimp. Accuracy is excellent.

This is simply not true. I have had great results with hard cast lead bullets in several Glocks 17, 21, 22, and 24L. After 40,000 rounds or so of lead bullets through my Glocks I have complete faith in them.
 
Quote:
"Poly bores require lead sized differently than conventionally rifled bores.

A poly bore actually compresses the bullet and rotates it about an axis where as a conventional bore only causes the bullet to rotate around an axis. Due to this, this is why jacketed bullets are recommended in poly bores, from Glock, H&K, et al.

The first step in running lead in any poly bore is to slug the barrel. I bet you'll find that lead should be sized one or two thousands over conventional deminsions for the bore. Most 9mm lead is .356", a Glock needs .358", generally. An undersize bullet will lead to leading, all the time, every time.

Also, hard cast isn't always better. Upon firing, the bullet "expands" from the pressure to seal the bore. In a low pressure round, like .45 ACP, a 11 BHN will expand sufficiently. In 9mm though, something harder, maybe in the 15-22 BHN range, is needed to seal the bore under the higher pressure. Have an improperly hardened bullet, you will experience leading, since it won't seal the bore and lead to gas cutting.

Don't forget twist and bore profile (hex vs. oct) either. 9mm and .40 are naturally less friendly because of more agressive rifling and hex bore profile, compared to .45 and will require a bit more due diligence.

Lube also plays a part. Lar's Red works well in most pistol applications and most rifle applications. Any good commericial lube should do, ALOX, LLA, Lar's, SPG, et al, or home made lube (Felix)."

Source:
http://www.glockpost.com/forums/showthread.php?t=118
 
I have found that .40 and .45 lead bullets work fine in Glocks using the industry standard diameters of .401 and .452. The alloy used was also the idustry standard formulation (92/6/2). The only change I had to make was to replace .356 standard 9mm bullets with .357. I use Thompson's lube as it is the best I have found; he has a web site.

A point to consider. I polygonal barrels can't handle lead bullets, why didn't this problem arise when H&K started selling these barrels 30 years ago? I can remember several shooters that loaded their H&K P 9s with lead bullets and got great results.
 
Ruger made a convertible model Blackhawk that came with both a 9mm and .357 cylinder. They were satisfied that the diameter difference between the two bullets wasn't a problem when going down the barrel.
 
Ruger made a convertible model Blackhawk that came with both a 9mm and .357 cylinder. They were satisfied that the diameter difference between the two bullets wasn't a problem when going down the barrel.

This can be done if you use jacketed bullets only.
 
Can someone explain why polygonal rifling is used. Is it because of accuracy, cost etc. It seems that it is a poor choice because it limits you to only jacketed bullets. I only own Sigs and as a result have no experience with poly rifling. Walthers also use it.
 
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