9mm oal help

[area51]

Trying to load 9mm 124gr rn from Missouri bullets. Made a couple of dummy rounds to check the head space in my Walther p99 and the lc9... On the p99 I am getting a measurement of 1.064 ( cutting it 2 close I think )
On another note, the lc 9 is happy with 1.148. - Anyone here load for p99 and can chime in with their oal ?

 

[rcmodel]

No, but take both barrels out of the guns and seat short enough the bullet doesn't hit the rifling in the shortest one.

When correct, they should pass the "plunk test" when you drop one in the chamber.
It should plunk in with the case head even with the barrel extension.
Then fall back out when you turn the barrel chamber down.

rc

 

[Walkalong]

Like this:

http://www.thehighroad.org/showthread.php?t=506678

 

[area51]

Thanks RC and Walkalong....That's what I did to check my headspace. I am a little worried about the min OAL for the P99 loads. Don't want to compress any powder in the case... From my manuals, 1.064 is about the minimum...

 

[rcmodel]

What is your power & charge??

Unless you started out with a MAX load, there should be no problem seating shorter.

Just seat where you need to seat, start at the suggested Starting load, and work up until gun function is right.

If you are throwing empty cases into the next county it is too hot.
If you aren't, it isn't.

rc

 

[gamestalker]

A couple of things here to clarify.

First, OAL and head space are not the same thing. OAL is the distance from the tip of the loaded cartridge, to the head of the cartridge is the OAL, also referred to COAL (over all length, cartridge over all length).

Head space for an auto loading cartridge such as ACP type's is the distance from the mouth to the head and has nothing to do with the bullet what so ever.

Compressed powder charges are those developed with powders that are intended for such, and are among the slow burning as per application. Powders that can be loaded to a compressed charge are not going to produce unsafe or excessively high pressure just because they are compressed. AA#7, Longshot, and HS6 are some good examples of a slow burning powder for the 9mm in this respect. Even at maximum charges those type of powders will often operate at slightly lower chamber pressures than a faster burning powder, also loaded to a maximum charge. On the flip side, you would not want to try and develope a compressed powder charge using something like Bullseye, Clays, titegroup, HP38 or any other fast burner's because pressures are only going to continue climbing as the powder charge is increased.. Yet AA#7, LS, and HS6 in my experience will begin to decrease chamber pressures at some point in the work up, usually this happens at the compressed point, which is also consistent with published estimates.

As to OAL, this should be determined by each individual barrel. The plunk test is OK, but what I like to do is with the barrel out I hand chamber my round and try to turn it while fully chambered. if it is touching the lands it will usually not spin, and if it does I can positively feel the resistence and also see where the bullet was contacting the lands when I remove it.
GS

 

[area51]

What is your power & charge??

Unless you started out with a MAX load, there should be no problem seating shorter.

Just seat where you need to seat, start at the suggested Starting load, and work up until gun function is right.

If you are throwing empty cases into the next county it is too hot.
If you aren't, it isn't.

rc

Thanks RC ! 3.8gr hp38 over the mb 124gr rn

As to OAL, this should be determined by each individual barrel. The plunk test is OK, but what I like to do is with the barrel out I hand chamber my round and try to turn it while fully chambered. if it is touching the lands it will usually not spin, and if it does I can positively feel the resistence and also see where the bullet was contacting the lands when I remove it.
GS

Good tip. Thanks GS !