Blue Bullets 180gr RNFP vs SNS 180gr TCFP

[Jay870]

I have a new pistol with a 1911 KKM bull barrel that does not seem to like the profile of the SNS 180gr no lube-groove bullets I have used in my other .40S&W pistols. They fail to plunk and spin even when seated all the way down to 1.10. 

 

I have a handful (literally) of Blue Bullets 180gr RNFP that a friend had given me a while back and those will plunk and spin freely at 1.160. 

 

Since I have such a small sample of the Blue Bullets I am just wondering if anyone else has found the Blue Bullets RNFP profile to allow longer COAL than the SNS TCFP profile (understanding that it will vary from barrel to barrel).

[R1_Demon]

This may sound like a stupid question, but I have seen on some of the ammo sites where they will mention .40 bullets with .400" sizing and .401" sizing.  Is it possible that your SNS bullets are the larger sizing and that is causing your problem?  While the Blue Bullets are the smaller sizing and are passing the plunk and spin with no issues due to that .001" difference?

 

I'm just guessing here and trying to shoot out some food for thought is all.  I know that isn't much of a difference, but adding on the case and all that, maybe it is enough to cause issues in the barrel?  I just know I have seen some bullet manufacturers say something like "down to .400" " instead of it being the .401" standard or something like that.  Just shooting in the dark here.  Maybe someone else has a better thought for you.  Maybe you could pull the bullets and measure them to verify the width?  Or check the width of them as they are in the cases and see if there is a difference and that is why they aren't passing the plunk and spin test?  Maybe they are too wide instead of too long?

[jcc7x7]

I received a box form them that was 402 and wouldn't feed in my Akai but would in other 40's I have.

they offered to replace the bullets, so no harm no foul just some agro,

Mic the bullets as stated above

[Jay870]

SNS TCFP on the left. Blue Bullet RNFP on the right

 

[pete627]

On 5/3/2017 at 0:51 PM, R1_Demon said:

This may sound like a stupid question, but I have seen on some of the ammo sites where they will mention .40 bullets with .400" sizing and .401" sizing.  Is it possible that your SNS bullets are the larger sizing and that is causing your problem?  While the Blue Bullets are the smaller sizing and are passing the plunk and spin with no issues due to that .001" difference? > snip <

+1

The SNS 40s "are" .401 by default .. you have to ask for .400. I'm sure Demon is correct ... this is your problem.

I recently tried a bunch of Bayou 40s that were .401 and noticed that I couldn't load longer than 1.16 or they would stick to the rifling in both my MP40 as well as my Para 1640.

It shocked me the first time I went to rack the slide and they stuck but then I had an "oh yeah" moment and realized it was the bullet diameter. Not a biggie ... they shot great ... just a consideration if you want to stretch out your OAL.

[sstephns]

I load 180 gr blue bullets in my CK with a KKM barrel to 1.175. Runs like a scalded dog

Edited May 8, 2017 by sstephns