confused on oal on 9mm bullets

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sixgunn

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im having a hard time understanding the oal of a 9mm bullet. the manuals seem to read 1.169 oal , but when i look up the manufacturers specs they say 1.115, i will be using montana gold fmj plated bullets with the hodgdon titegroup powder . it just seems like a big difference in lengths and from what i have read it seems to make a big difference in 9mm on how deep you seat them . any help would be much appreciated and thank you for your time :)
 

pak-40

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im having a hard time understanding the oal of a 9mm bullet. the manuals seem to read 1.169 oal , but when i look up the manufacturers specs they say 1.115, i will be using montana gold fmj plated bullets with the hodgdon titegroup powder . it just seems like a big difference in lengths and from what i have read it seems to make a big difference in 9mm on how deep you seat them . any help would be much appreciated and thank you for your time :)

1.169 is MAXIMUM OAL. 124g FMJ bullets are "taller" than 115 FMJ bullets. When loading 124 FMJ or 147 FMJ, the the rounds will be "taller" than when loading 115g FMJ. Hence, the increased Over All Length (OAL). Seating bullets too far to get your OAL down can increase pressures quite a bit. Be careful.
 

Rod Snell

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Two things determine the "real" maximum OAL in YOUR gun: The room in the magazine and the point at which the ogive hits the rifling. The MINIMUM length
is determined by how much of which powder you use in the available space before you blow up your gun.
As Pak 40 said, the 9mm Luger is a real hazard to arbitrarily seat the bullet deeper, because the expansion ratio for a small-volume case does not leave much room for error.
Pressure increases near the max are NOT linear, so if the bullet does not hit the rifling and fits in your magazine, I'd go with the load data for the specific bullet, not try to use a general rule.
 

sixgunn

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aha well that helps alot , i didnt know the bullets were different lengths , i have a lymans book but they dont show 115 grain rn specs , i have loaded plenty of 45s without any problem but the 9 mm seem to be more dificult and a little more finicky i guess , thank you for your informative responses .
 

F16mickey

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another thing ur AOL will change with the type of powder u use
OAL will not change with the type of powder it will change with the projectile. Ie. hollowpoints are not usually loaded to the same OAL as FMJ.
caveat always use published load data (from a manufacturer) and try to find a similar projectile.
 

Glocktogo

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The bullet profile is the deciding factor. For example:

Most 115gr FMJ: 1.115"
Win 147gr FMJ ENC (flat point): 1.115"
Speer Gold Dot 115+P+: 1.12"
Win Ranger 127 SXT +P+: 1.12"
Speer 147 Gold Dot: 1.125"

Some handloads for practice and competition:

Berry's 115gr Plated Flat Point: 1.055"
Montana Gold 115 JHP: 1.105"
Montana Gold 147gr FMJ (Flat Point): 1.140" (set up for an STI 9mm)

The bullets are seated based on optimal pressure curve and feeding profiles, not necessarily bullet weight.
 

sixgunn

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:screwy: i just picked up a new box of factory 9mm fmj bullets and they measured 1.165 to 1.172, to me logically the rn fmj would protrude the farthest out , much more tha a swc or hollow point would but 50 thousands seems like a lot of difference in bullet lengths but im finding more and more on manufacturers websites the 1.115 oal to be the standard. montana gold does not specify anything on theyre website so i might email them monday to see if they have any recomendations.
 

jduff8505

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I load my 125gn lead round nose with 4.3-4.5gn 231 powder to an OAL of 1.155 it seems to work for me. I'm relatively new to reloading so a lot of this is still smoke and mirrors to me as well. How do you tell where the bullet is in the barrel when its in the chamber?

Jeff
 

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