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Norone

Need a link to the .355/56/57 debate...

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Hey y'all,
Running molys at 147gr in a Glock 34 with a KKM barrel. I could swear the larger 356-7 are more accurate. Seems this way in my G35 with 200's at major. Anyone have a link or info on this worn out debate?
 

Thanks!

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If there's no info links do you guys have opinions? Better results from 356-7 or 355?

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I always try .001-.002 over and check function first, some won't plunk or feed in some bbls

Then I shoot for accuracy.

Usually .002 over " normal" are more accurate,

Ie with lead or hytek coated.

 

As an example I shoot .358 out of my 9mm, Sig's,xdm, couple of 1911's etc

All are more accurate with them than 355/6 dia. Bullets

Again talking lead or coated lead

Jacketed I shoot

356 dia

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Order a 100 pack of each size and shoot them

Proof is in the pudding! Puddin!

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Ha! Thanks man. I will do so.

 

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4 hours ago, jcc7x7 said:

Order a 100 pack of each size and shoot them

Proof is in the pudding! Puddin!

 

This is the answer.  Your gun is the final judge and it will tell you which diameter it prefers. Keep in mind, they might all be equal.

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N, the very first thing you should do is slug your barrel.  9mm barrels range fro .355" on the tight side (think Sig) and .359" on the sloppy side.  As a general rule, lead bullets .001" larger than your groove diameter are the most accurate.  You still have to test, because on rare occasions best accuracy is obtained with a groove diameter lead bullet.  Other times you have to go more than .001" over.

 

As an example, my CZ TS and both 2011s in 40 sw shoot same hole groups at 15 yards with .400" Rainier plated bullets.  They did the same thing with Gen1 Precision bullets (.400").  Precision went to Gen2 and .401 and they are not as accurate.

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One way that caused me to start looking at the undersized bullets was I had a load that was shooting a low extreme spread in one gun and high in another gun so I slugged the one with the high Es numbers and sure enough it was about a half a thousands over .356 dia. Coated bullets I was shooting. I ordered some .357 dia.coated bullets for it and all was good.

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I would not recommend slugging your barrel. 

 

If slugging your barrel told you that .356 was ideal, but you found that .355 or .357 shot better than .356, would you shoot .356 anyway?  Of course not.   So why bother slugging? 

 

Just buy some of each, and see what works.  

 

Personally I have not seen a 9mm that wouldn't dial in with a jacketed bullet at .355 or .356.  I keep 124gr .355 and .356 Precision Delta jacketed on hand.   If your pistol prefers .355 jacketed, it might perform optimally with .355 lead and will perform optimally with .356 lead.  If your pistol prefers .356 jacketed,  it might perform optimally with .356 lead snd will perform optimally with 357 lead, and even .358 lead may be great. 

 

Rule of thumb: your barrel will perform optimally with lead .001 larger than its jacketed ideal. 

 

And if your barrel is so over-sized it prefers .357 jacketed, get a new barrel. 

 

Just get some 355 and 356 Precision Delta jacketed for your "sizing" experiments.  1000 of each?  It is not like any will go to waste.  ;)

 

Cheers.  :)

 

Edited by IDescribe

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On 11/7/2018 at 11:32 AM, Norone said:

Hey y'all,
Running molys at 147gr in a Glock 34 with a KKM barrel. I could swear the larger 356-7 are more accurate. Seems this way in my G35 with 200's at major. Anyone have a link or info on this worn out debate?
 

Thanks!

Coated, plated or plain lead use a .356

If you use harder bullets jacketed or lead free go .355

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