9mm 115g JHP OAL question....

[sjg1966]

Howdy....

Newbie question here: I plan to start making some 9mm rounds and I am going to use Montana Gold 115gr JHPs. I have three manuals (Lyman, Lee, and Hornady) and all three have varoius OAL from 1.075" to 1.125". Their data is from the Hornady 115gr XTP bullet. So where should I be with the OAL?

I was thinking I'd start in the middle (1.09"ish) and check to see if they chamber properly in the removed barrel from my P226 and fit the mags proper as well. Am I thinking in the right direction or?

Using W231 for my powder if that is a factor......

Thanks in advance for your help.....

Steve

[Tythagoras]

You aren't thinking in a bad direction. The max spec is 1.169. I would run near there, since the chamber in my Springfield EMP is long and can accommodate max spec rounds, except that if most of the rounds are 1.165 or so, a few statistical outliers will seat longer and jam in the magazine. So I load mine at 1.150 or so. This is mostly for 124/125 grain loads, though. 115s leave less bullet shank for the case to grab onto.

Also, do your pressure testing at min. OAL, because the less space the power has to burn in, it will develop greater pressure. That way, if you load longer, and the bullet gets pushed back a little by hitting the feed ramp, you aren't suddenly in uncharted territory with regard to pressure.

231 is an excellent powder for 9mm.

[HighLander51]

Winchester Reloading Data is showing 1.125" at 4.7-5.1 grains of W231. The 115 is a short bullet, so it needs to set a bit further back in the case. And you can't measure pressure, only muzzle velocity.

[Bill Steele]

In general, most published loads will come with an OAL. That is referred to as the minimum OAL as that was the deepest the bullet was tested to by the developer of the spec. It doesn't mean you can't seat deeper, it just means you are on your own load development wise if you do seat deeper.

I general I seat my 115gr and 124gr to 1.145". The reason I use that length is all the loads I use call out an OAL of 1.145" ot shorter, so I know I am OK OAL wise. Also, 1.145" feeds reliably in all the guns I own.

The one exception to the above is if I am loading a bullet like a Hornaday XTP or a Precison Delta 124gr JHP, that have a very abrupt shoulder break, so the bullet goes from .355" in a straight line to the point. This shoulder will sit up very high when seating the bullets to 1.145" and some of my guns have a tight enough throat that the round won't chamber properly. In these cases I have specific loads I use to allow me to seat deeper and keep the shoulder from interfering and causing chambering problems.

TMI?

[sjg1966]

Bill...

Not TMI. Thanks. You actually touched on part of the reason I asked. The Montana Gold 115 JHP are shaped just like the XTP and the data from the three manuals I have used the XTP too. How deep do you set those XTPs Bill?

[Bill Steele]

Bill...

Not TMI. Thanks. You actually touched on part of the reason I asked. The Montana Gold 115 JHP are shaped just like the XTP and the data from the three manuals I have used the XTP too. How deep do you set those XTPs Bill?

I think the right answer is it depends on the gun you are using. For instance, my Glocks, Ruger SR9C, Beretta 92FS, etc. all have throats that allow me to chamber and feed 124gr XTP's, MG JHP or PD JHP's (with the abrupt break at the shoulder), at 1.145" OAL. My Kimber Stainless Target in 9mm is a little tighter, so I have to seat those at 1.130" to assure flawless feeding.

There was a guy on these threads the other day who had a Walther (I think), that wouldn't chamber these style bullets unless they were really seated down (shoulder very close to the case mouth).

A smith will tell you they should chamber to the maximum OAL for the caliber and can throat the barrel slightly to accomodate this objhective. It doesn't take much in the way of throating to accomplish this aim. For me, it is easy enough to load the bullet to the length the gun likes, I mark these "For Kimber", all others are unmarked.

I tried some lead 125gr TC's in 9mm a while back. These are .356" and also have the abrupt shoulder break to a flat nose. Almost none of the 9's I own would chamber these rounds unless I seated the bullet so the shoulder was just above the case mouth or deeper. They also wouldn't stabilize in many of my guns, totally confused why that was. I don't buy these anymore.

I hope that all made sense.

Good luck, have fun.