C.O.L vs. minimum case engagement

M

mjes92

New member
I'm sure this not a new twist on an old question. COL has more to do about fitting a round to a particular chamber. With pressure issues to consider. Where my questions really starts is when the COL is capable of having very little bullet to case engagement. How much is to little?

I'm working up a few test rounds for a G19. As I seat the bullet to maintain the classic "Plunk" sound when dropping it into the chamber I realize the case/bullet engagement is only about .100". Is that a safe amount of engagement?

9mm Load #1 data=
5.0 True Blue
124 gr. X-treme FP (flat point)
CCI small pistol primer
C.O.L = 1.160" (max. length to fit in mag.) 0.100" case/bullet engagement.

9mm Load #2 data=
5.0 True Blue
115 gr. X-treme HP (Hollow point)
CCI small pistol primer
C.O.L = 1.150" (max. length to fit in mag.) 0.080" case/bullet engagement.

Am I exceeding a C.O.L rule? Still safe at these numbers? The "Plunk" test sounds perfect for both loads.

Thanks
 
Interesting question that I have asked to myself. How far out can one load a bullet before it starts to effect neck tension?

I have one 9mm that I could load both a Berry's RN 115gr and 124gr out to 1.175" but they will not fit into the magazine.
 
mjes92,

What you are referring to is called seating depth.

Seating Depth = Case Length + Bullet Length - Cartridge Overall Length (COL)

The rule to observe factory maximum COL is only for manufacturers who need to ensure their ammunition fits the magazines of all 9 mm pistols made. You have your particular pistol, so you can load to whatever it will tolerate and still work well. 0.100 inches is pretty small engagement. The concern is it will tip the bullet off-axis during feeding, but if the accuracy you get is good, then that's not a problem for your gun.
 
The question was ......Am I exceeding a C.O.L rule?
I was Wondering if there was one.

Loading to 1.160 is the max length that will function and load in the magazine.
 
Thank you Unclenick.

It was one of those “this doesn’t feel right” situations.
Only testing will tell the whole story. So far the G19 eats up everything I feed it.
 
mjes92 said:
The question was ......Am I exceeding a C.O.L rule?
I was Wondering if there was one.

Loading to 1.160 is the max length that will function and load in the magazine.
Click to expand...

The OAL guide is:

You can load to any OAL you desire as long as it fits in the magazine and chamber and feeds reliably.

If you load the exact same bullet shorter than the source you're getting load data from, you might need to reduce your powder charge to avoid increasing pressure too much.

There is no rule that says you have to load to the longest OAL that will function and fit in the magazine.

If you look at various loading manuals for 9mm data you'll see that they load bullets to a variety of OALs.
 
"...if there was one..." Yep. SAAMI specs cover COL.
1.160" is not the max for 9mm either. 1.169" is max for 9mm Parabellum(minimum is 1.000"). That's from the pointy bit to the flat bit too. No ogives involved.
The cartridge length is not about the bullet weight though. It's the max OAL for 9mm with any bullet. If a 1.169" 9mm doesn't fit your mag, there's something terribly wrong.
1.175" is too long and should not fit the mag or the chamber.
"....100 inches is pretty small engagement..." Yep. A whole Hornady 115 grain HP XTP is .538" long. A 124 is .603" long.
 
Or more relevant, does seating way long in 9mm get you anything?

I have not found a COL max to have the kind of results rifles have.

There getting toward or into the lands for some guns seem to work and I do have one combo that likes it. Mostly not.
 
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