9mm trimming and COAL- HELP!

M

MTSig89

Inactive
Hello everyone!

I am relatively new to reloading and just started some loads for my Sig Mk25 9mm.

I am using the Lyman recipe for 115 grain FMJ's with 700x powder (all I could find :eek:) which calls for a 3.1 grain charge as a starting load. I have an RCBS carbide die set which includes a taper crimp die. Spec from the book calls for a crimp of .001-.002" and COAL(cartidge over all length) of 1.090". I have some factory new brass as well as some range brass- it has all been sized (deprimed as needed), chamfered and deburred and now I am setting up my seating/crimp die after charging each case with powder.

I have found quite a lot of information concerning whether or not to trim straight wall cases. Based on my research and findings I don't disagree with those of you who don't feel it's worth it to trim your "standard" straight wall cases I.E. NOT mag's or +P's. I do, then, have a concern with my COAL. I have been led a bunch of different ways on this and since there isn't a ton out there for pistol loadings concerning seating depth, cartridge overall length and case pressure I figured I would try to start a conversation. My experience in reloading has been for wheel guns (.357mag, .41mag and .44mag) and bench/hunting rifles (.223, .260, .270, .338 etc....) and ABSOLUTELY no exeperience with a semi-auto gun hand loading.

Again, my recipe is for a starting charge to get a feel for how the rounds will perform in my particular weapon, so I don't believe I will have pressure issues.

Basically what I want to know is if anyone has an opinion or experience with this cartridge and has seat depth variance preferences that are within "acceptable" limits. I loaded 100 cartidges of the range brass and pulled 20 cases with maximum variance of .007" below or above COAL value of 1.090", with several that were bang nuts on. I found on this forum a guy who claimed .010" plus or minus should not render real consequences if a guy is attentive to his loads and how they perform.

Any and all input is much appreciated as I have found a ****load of info for rifle cartridges and very little on semi auto loadings.


Thanks in advance!
 
Hell, I'll go first and start all the controversy.
I too load for 9mm with the over all cartridge length of 1.090 AND, plus or minus .010 length with never an issue. As far as taper crimp applied to the
thousands...never do I use this method, I just taper crimp until I can't seat
the bullet any deeper while pushing the bullet/cartridge into my loading bench.

I hope this helps.
 
I will also mention that when you choose other bullet nose styles, to load a few
test dummy's...no powder, no primer to see if they'll function up the ramp.
 
Hell, I'll go first and start all the controversy.
I too load for 9mm with the over all cartridge length of 1.090 AND, plus or minus .010 length with never an issue. As far as taper crimp applied to the
thousands...never do I use this method, I just taper crimp until I can't seat
the bullet any deeper while pushing the bullet/cartridge into my loading bench.

Smoke & Recoil-

I wonder if you might expand of your first response. My die set dictates to set seating depth first, then the crimp. I'm afraid I don't understand.
 
Yes, set the OAL first, then back out the seating stem, then lower the seating die just a slight bit to achieve the desired crimp, then reset the seating stem to your OAL length.

#1, seat bullet to length

#2, back out seating stem

#3, lower die to adjust crimp

#4, readjust seating stem to the top of bullet.

You can also get a Lee Factory Crimp Die and crimp separately too, that works great.
 
I am an Amazon Prime member and found the Lee factory crimp die for just under $17, it's on the way with a Hornady manual and a case tumbler from Frankfort Arsenal.
 
1) Don't trim straightwall cases. Even trimming to get consistent roll crimps (for revolvers) has no effect on accuracy.
2) COL is the reloader's responsibility and the COL in a manual is NOT a recommendation.
Per Ramshot (and all other reloading suppliers):
SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must
be seen as a guideline only.
The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
This parameter is determined by various dimensions such as
1) magazine length (space),
2) freebore-lead dimensions of
the barrel,
3) ogive or profile of the projectile and
4) position of cannelure or crimp groove.

• Always begin loading at the minimum "Start Load".
• Increase in 2% increments towards the Maximum Load.
• Watch for signs of excessive pressure.
• Never exceed the Maximum Load.

Your COL (OAL) is determined by your barrel and your gun and your magazine. What worked in a pressure barrel or in my gun has very little to do with what will work in your gun. Load a couple of dummy rounds (no powder and no primer) to the max. COL (OAL) and see if it fits your magazine, feeds in your gun, and chambers in your barrel.
Seat the bullet slightly deeper until you achieve all three of these goals. This is the COL (OAL) for you in your gun with that make of bullet. You are the one in control. Enjoy it. You can make ammunition tailored to your gun and not have to load to the minimum COL (OAL) as do the factories.
3) Variations in COL is not very critical, unless (maybe) you are pushing pressure limits. Measure your bullets' OAL and measure factory round COL and see the variation you get. +/- 0.010" is really not a big deal and, if it is, what exactly are you going to do to decrease it? Finally, if it was REALLY a critical dimension, wouldn't all manuals note this and explain how to reduce the variation?
The whole "fear" of COL started when it was shown that a factory 9x19 round that produced about 33ksi, produced 60ksi when the bullet was seated 0.25" deeper. That is ¼" and NOT 0.010". Before that (for the last 90 years or so), folks just accepted what they got and if they couldn't SEE the difference, they ignored it.
The critical thing to ME is to push down on the bullet after seating to ensure that it doesn't move--and possibly seat 0.25" deeper during feeding.
 
The separate crimp die is great in my opinion, it takes a lot of readjustment out of the equation.

I shoot 8.0 gr of Blue Dot through my 9mm with a 115 gr FMJ bullet.

What type press do your use ?
 
noylj:
Thank you for your input. Every opinion is much appreciated.


Smoke & Recoil:
I have an RCBS RS5 press. Hornady LocknLoad powder measure and a Hornady analog scale. Right now I am hand priming with the RCBS tool and love that! Eventually a progressive loader will be on the bench, as competition shooting is the goal and a single stage just doesn't make sense.

On the other hand I have only loaded a handful of times with a VERY experienced loader and grew to appreciate the pace and accuracy of single stage loading. In my opinion it's the only way to start so you don't find a problem 50 cases in.
 
MTSig89,
Seem's you have a good grasp on what you're doing and what you want. Remember, you'll get many opinion's coming along, so you'll have to form
your own too.
If you need an answer...ask and read then repeat.
 
MY Lyman No 49 does not show a 9mm 115 gr FMJ.
They tested 115 gr loads with a JHP.
A JHP usually loads to a shorter OAL than a FMJ unless that FMJ is a flatpoint.
Is yours?

I load roundnose or truncated cone 9mm to about 1.14"
 
This reads like the blind leading the blind.

First understand that a 9 mm case is a tapered case. Not greatly but slightly tapered. Second you need to understand that semi-auto pistols index on the case mouth and by trimming them you stand a chance of getting too much head space between the head of the case and face of the slide. Cases lengthen due to over pressure loads and you want to avoid those to begin with. Pistol cases don't stretch the same way rifle cases do. Generally there is no need to trim semi-auto cases, like 9 mm.

Unless you are using cast lead bullets, the proper OAL for a load is published by the bullet manufacturer. It is more a function of internal case pressure than an issue of how close to the lands you need to be. In most pistols that is a non issue since the barrels are so short. You will find that the chamber of your pistol is 0.020 larger than the bullet so it will accommodate the case and the rest of the barrel will be 9 mm the rest of the way through (.355).

There is a ridge inside the barrel the length of the case and that ridge is where the case rests and is index on. (see: SAMMI for the dimensions)

While starting at the min of your load data for powder is safe, it generally ends up being to light a load to cycle your slide and eject the case properly. I would suggest using half way between the min and max load as your starting point and then work your way up on any new load for pistol.

Good luck and stay safe.
Jim

You also do NOT crimp pistol cases, revolver cases yes, pistol cases no. You stand a chance of the case not indexing on that ridge in the barrel and forcing the case too deep into the barrel and causing a bullet not to be able to move and blowing up your gun. I use my Lee FCD just to insure the flare on the mouth of the case is set back properly after flaring the case in the powder through die. No crimp just the correct size of the mouth of the case. Also crimping a pistol round stands the chance of deforming the bullet and making the bullet looser causing a bullet set back into the case and increasing the internal pressure of the load to be dangerous.
 
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I do not EVER trim 9mm. I have loaded the same brass over and over until the primers fall out and have never needed a trim. use the FCD for a crimp on inconsistent length brass if you need to. your OAL will depend on your bullet. MY maximum oal is 1.120 because that it what will reliably cycle in ALL my 9mm pistols and rifles. I have small 90gr hollow-points that get loaded as short as 1.050. most 125gr HP's get loaded to 1.090 in my house. I don't get concerned with OAL unless I am really pushing the envelope on max loads.i do use my seating die to put on a little crimp and take out the bell.

I am finding that I am starting to need to trim .357mag cases to get consistent roll-crimps, but that is not to concerned with 9mm. with 9mm, just don't overthink it, make some rounds to different degrees of depth and find what feeds best in your gun while not going too short to hinder accuracy or "increase pressure", in quotations because I have never seated a 9mm too deep to ever cause over pressure signs.

9mm is a very easy round to reload for, and I commend you for being professional coming into it, but I think you will find too much effort will not yield you improved results over just loading to what your gun likes. back out that seating die and use the stem to just take the bell out and barely give you a crimp
 
Jim243:

I plan to test fire my first 200 loads (as described above) with due respect to all indicators of foul play. By all accounts the Lyman book is a reliable manual for reloading, and a Speer manual my mentor leant me confirms my recipe is at the very least reasonable. Because I have a measure of attention to detail I will play it safe first and kick myself later, as needed. Better to be safe (as per the manual) than sorry, yes?

Skizzums:

I have found in the past the I can over think things :) I have found, though, that my methods of over thinking/over researching has been of benefit. I feel that this case is no different. I think this forum is an excellent medium to explore and debunk any crazy ideas before taking unsafe rounds to the range, but realize attention to detail only gains so much.

Again, everyone's input is MUCH appreciated!


Regards
 
Your starting load of 3.1gr seems low since Hodgdon has a starting load for 115gr lead of 3.3gr and 115gr GDHP of 3.9gr and 124gr plated of 3.7gr.

i would suggest to only load 5 rounds at 3.1gr and see what you have. My gut feel is going to be a very light load with the brass maybe extracted into your face or very close to you.
 
I do not load 9mm with 700x but my Speer #11 shows 4.3 - 4.8 of it with a 100 grain bullet so I know that your loading is way wimpier then I would start at.

I use Green Dot, Red Dot, HS6 and Unique for loading 9mm.
 
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Agree with vaalpens, a 69% of maximum load may well not even cycle the slide. 200 rounds would be a frustration. I don't know why Lyman shows such light starting loads, the usual rule of thumb is 90%. A 1911 is pretty flexible but Sig is not. I tried loading down my P225 for a beginner and 88% was the lowest I could go and the gun still function.

If you have not already cranked out that 200, load a few and shoot. Better, load a few at .2 grain intervals up to 90% and test. Work up from there if you need to.
 
Every manual can ONLY report what they got with the gun, bullet, and lot numbers of components they used. They variation in manuals shows the variation any one can get as they use a different gun, almost certainly a different lot number of bullets (if they even have the same bullet) and different lot numbers of components (and, most likely, not even the same brand of primer or case).
There is no ONE manual to rule them all. One should check as many as possible and start at the lowest starting load one can find.
5 rounds that don't cycle is a lot better than 5 rounds that are max or over max.
So, if there isn't a lot of load data, start a bit lower yet and work up.
 
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