9mm FMJ Question.


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45taurus
February 20, 2011, 05:31 PM
I'm looking into getting a 9mm 124gr .355 FMJ from Montana Gold bullet.

Hodgdon Load Data has a load for a
125 GR. SIE FMJ .355" 1.090 C.O.L.
4.4 Min. 1009fps 24,600 CUP
4.8 Max. 1088fps 28,800 CUP

Can i use the bullet from Montana Gold Bullet (9mm 124gr .355) with the hodgdon load data from above? I know its a different bullet that they list but its only 1g difference. Other than that its the same bullet just from a different manufacturer correct? So can i substitute it and still use the same load information or will i run into issues with that?

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smokinjim
February 20, 2011, 05:51 PM
I'm not an expert but I would say yes.
Your bullet is one gr less so no additional pressure but may pick up a little velocity.

mbruce
February 20, 2011, 05:52 PM
Yes. The high rollers will explain why in a few...but to get u up and going...yes.

I'm assuming you are using a hodgdon powder and the load data mention is for THE SAME powder you are loading with.

Is this the 231 that we all chimed in on your earlier post?

45taurus
February 20, 2011, 06:29 PM
yeah w231 i found the montana gold FMJ bullets to be the same price as berry's plated bullets. I figured i'd just load w231 with the 124g montana gold bullets at about 4.6g. Do i use the same OAL also?

mbruce
February 20, 2011, 07:57 PM
dont go below the OAL on the hodgdon website and don't go longer than what you're gun will reliably feed....

Don't let the OAL worry ya....the book will give a "max" and "what they used" the website does not give a max but does give a "min"...so a simple answer is use what the book said use...if you only have the website then don't go below what that website goes...

if you need to check to see if it will feed in your gun.....start long and shorten it until it smoothly goes from your magazine into your chamber...it's also wise to take your barrel out and drop the cartridge into the barrel...you should hear/see if something is wrong....to verify what looks good then take some factory ammo that you know feeds reliable and drop it in your barrel..mimick that same depth and sound and you'll be rocking and rolling...
you can always lower it until it's just right.... just don't get too wild with compression to where it looks like a sabot slug and you'll be ok. and dont go below what's on the website.

I know there are some HP that seating does make a difference...but that is another topic.

sorry if its written horribly---i'm in a room with a lot of folks typing on a phone.

RidgwayCO
February 20, 2011, 08:33 PM
CAUTION! The following information might be helpful...

Speer #14 says that in 9mm Luger with their 124gr TMJ bullet to use a range of 4.0 - 4.5gr of W231, and this is with a COL of 1.135". Since Speer isn't noted for too many "lawyer-ized" loads, I'd recommend proceeding with caution. QuickLOAD doesn't indicate a problem, but I'd trust pressure-tested loads by a major manufacturer before I'd trust QuickLOAD.

As always when reloading, start low and work up slowly, looking for signs of excessive pressure in your gun.

45taurus
February 20, 2011, 08:47 PM
Why does it vary so much? I dont understand, that is a big difference. Speer says 4.0-4.5 and hodgdon says 4.4-4.8. so between the two its 4.0-4.8 Thats a big difference. Which do you go with?

noylj
February 20, 2011, 08:47 PM
Rule 1: start with the starting load and work up.
Rule 2: you can use the data for a heavier bullet of the same construction for a lighter bullet.
Rule 3: Bullet construction breaks down to:
a) lead bullets (this includes moly-koted lead bullets and thinly copper-plated lead bullets--such as Rainier)
b) jacketed lead bullets (this includes thickly copper-plated bullets such as the "bonded" bullets like Gold Dots).
c) lead-free bullets that are generally pure copper and need specific loading data
d) frangible bullets that need specific loading data.

I have always used any lead bullet data for any lead bullet and any jacketed bullet data for any jacketed bullet I am shooting. The main areas to follow are:
1) start with the lowest starting load found after looking at several loading manuals
and
2) load to the maximum COL that fits your magazine or cylinder and feeds and chambers easily in your gun.
Never ever assume that someone else's pet load will work for you. Always find out what the lowest starting load is from several manuals or reduce the load by at least 10% and start there.
This isn't rocket science, so don't complicate it unnecessarily, but always remember the safety rules.

mbruce
February 20, 2011, 08:50 PM
Use the load that your powder manufacturer says use.

RidgwayCO
February 20, 2011, 08:59 PM
Personally, when I see such a large difference between major manufacturers (which happens more than any of us would like to see), I chronograph the lowest starting load just to get a "reality check." If it corresponds with the published velocity (corrected for barrel length), then that's my starting point for load development. If it chronographs much less than expected (which is usually what happens), then I proceed to chronograph the starting load for the next higher published data.

Notice how, without a chronograph, you have no real idea where you are in terms of pressure. Just an observation...

1SOW
February 20, 2011, 10:06 PM
I use (on and off) the 124 MG FMJ.

That Hogdon/Sierra 125gr bullet load data gives an oal of 1.09" which is waaay short of typical 124 FMJs.

MG 124 FMJ/TMJ, 4.3 gr 231, at 1.125 should give you about 1040-1050 ft/sec--light load. I've also loaded them out to 1.14" with 4.0 n320 at the same speeds.

Sunray
February 20, 2011, 10:42 PM
"...So can I substitute it..." Yep. The single grain won't matter.
"...gives an oal of 1.09"..." Agreed. That has to be a data entry error. Should be 1.125". 1.090" is for a 115.

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