Powder charge for cast 9mm

[sOhioJoe]

I've finally got my 120gr Lee TC bullets to chamber in the new lone wolf barrel. I had to seat them at 1.065" and I'm seating and crimping them in separate steps. My question is, how many grains of Unique would be a good starting point? Any other comments or concerns on seating 9mm cast bullets this deep would be appreciated. Thanks

[johnnysespresso]

Lyman Cast Bullet Handbook #4 lists a 120gr round nose seated to that AOL with 4 to 5 grs. of Unique. I would load 10 or 20 test loads with 4 to 4.5 grs of Unique and see how your Glock likes them

[Ickisrulz]

http://www.amazon.com/s/ref=nb_sb_ss_i_0_10?url=search-alias%3Daps&field-keywords=lyman%20cast%20bullet%20handbook&sprefix=lyman+cast%2Caps%2C237&rh=i%3Aaps%2Ck%3Alyman%20cast%20bullet%20handbook

[runfiverun]

here's how i guesstimate a starting load for a boolit i have but can't find data for.
i find several loads using the powder i want.
i use the same weight [and the next weight up if possible] and design if i can.
i compare how deeply they seat in the case compared to the boolit i have.
based on bearing length.
then i adjust my starting load based on the reduced or increased case capacity i see.
then i start a tick lower than i think i should and try a couple of small batches in that range.

[fecmech]

In the Lyman Cast Bullet handbook the data for their 356402 bullet IMO would be almost identical for the Lee bullet using your 1.065" oal. Disregard the Lyman oal as their bullet has a longer pointier nose than the Lee BUT bearing surface and amount in the case is identical. With case capacity,bullet weight, and bearing surface the same, pressure should be pretty darn close.

[MtGun44]

runfiverun nails it, as usual. Fecmech has the same (correct) concept.

LOA, by itself, isn't important to pressure, but the volume in the case under the boolit
base is crucial (controlled by LOA and boolit design), as is bearing length. If you are
reducing the case volume (combustion chamber) below that which the book LOA and
boolit produces, you should reduce the charge proportionally.

Bill

[dverna]

here's how i guesstimate a starting load for a boolit i have but can't find data for.
i find several loads using the powder i want.
i use the same weight [and the next weight up if possible] and design if i can.
i compare how deeply they seat in the case compared to the boolit i have.
based on bearing length.
then i adjust my starting load based on the reduced or increased case capacity i see.
then i start a tick lower than i think i should and try a couple of small batches in that range.

An excellent post

Don Verna

[Ed_Shot]

runfiverun nails it, as usual. Fecmech has the same (correct) concept.

LOA, by itself, isn't important to pressure, but the volume in the case under the boolit
base is crucial (controlled by LOA and boolit design), as is bearing length. If you are
reducing the case volume (combustion chamber) below that which the book LOA and
boolit produces, you should reduce the charge proportionally.

Bill

The Lyman 356402 has a boolit length of .624 and using the Lyman 4th Ed. OAL of 1.110 there is .264 of the boolit inside a 9MM case that is .750 long.

The Lee 356-120-TC has a boolit length of .560 and has the same bearing length as the 356402. So you could seat the 356-120-TC to an OAL of 1.046 and have the same boiler room used by Lyman's loads listed for the 356402.

I load the 356-120-TC to an OAL of 1.055 to suit my CZ 75 and use Lyman data for the 356402 and 356242 (120). The loadings do great in the Lone Wolf barrels for my Glocks.

[MtGun44]

Thank you for the specific numbers - good addition, clarifies the situation.

Bill

[Ed_Shot]

My first post to this forum, then a new 9MM owner, was to ask what OAL I should use for the Lee 356-120-TC. Mr. fecmech gave me great advice and insight comparing its dimensions to the Lyman 356402.

I totally agree with the excellent advice given by Mr. fecmech, runfiverun and MtGun44 above. The problem in applying this wisdom when you don't have data for your new Lee or RCBS or Accurate mold is that you don't know the dimensions (length & bearing surface etc.) of a comparable looking boolit in your reloading manual. Granted, you can ask an expert here but it sure would be handy if there was a sticky that listed the critical dimensions of the 9MM and 40 S&W boolits listed in the Lyman 4th Ed (for example). I once emailed Lyman to get the length of their 356637 HP and their reply included a variance of .02 .....I considered that useless. Anyway, my 2 cents.

[runfiverun]

sometimes you gotta wing it a little bit.
even if you have a 'book oal' sometimes it just won't feed through your gun.
so you again have to make a change away from what's published, and adjust the load one more time.

I have a 124gr rnfp I use in one of my 9m carbines it ends up having an oal of .95
so no where in the world do I have a reference for something like that.

in the past i have intentionally used a deep seated 158 swc [in a 9m] and bumped the load all the way past 4 grs of powder [before blowing the grips off the pistol] I learned what back it down means.
the load went from getting more accurate to fa-bloom in .1 gr.

when dealing with a pistol the first criteria is function.
100% of the time, every time.
otherwise you have a steel L shaped very close range club.
this means you have to set the oal of the round first.
then you determine the amount of case you have left.
then start low and work up until you get that 100% function.
this is when I get out my chrono-graph and see what velocity's I am getting.
I also look at the barrel.
is there unburnt powder in there?
dirty residue?
that's a clue as to pressure as much as the velocity is.
am I getting blow-bye when I shoot the gun?
soot on the cases?
those are signs of low pressure [good thing to have here]

the next is leading or a lube smear down the barrel a way's.
tipping or oblong holes in the target.
these are all clues as to pressure also.
the gun/target can tell you a lot of things if you look.

[tazman]

sometimes you gotta wing it a little bit.
even if you have a 'book oal' sometimes it just won't feed through your gun.
so you again have to make a change away from what's published, and adjust the load one more time.

I have a 124gr rnfp I use in one of my 9m carbines it ends up having an oal of .95
so no where in the world do I have a reference for something like that.

in the past i have intentionally used a deep seated 158 swc [in a 9m] and bumped the load all the way past 4 grs of powder [before blowing the grips off the pistol] I learned what back it down means.
the load went from getting more accurate to fa-bloom in .1 gr.

when dealing with a pistol the first criteria is function.
100% of the time, every time.
otherwise you have a steel L shaped very close range club.
this means you have to set the oal of the round first.
then you determine the amount of case you have left.
then start low and work up until you get that 100% function.
this is when I get out my chrono-graph and see what velocity's I am getting.
I also look at the barrel.
is there unburnt powder in there?
dirty residue?
that's a clue as to pressure as much as the velocity is.
am I getting blow-bye when I shoot the gun?
soot on the cases?
those are signs of low pressure [good thing to have here]

the next is leading or a lube smear down the barrel a way's.
tipping or oblong holes in the target.
these are all clues as to pressure also.
the gun/target can tell you a lot of things if you look.

This is excellent. Is there a sticky here somewhere that includes this type of information? If there is, I missed it.
I only know the very basics of what to look for when building up a new load and would love to have more details like these available.

[runfiverun]

not that I'm aware of.
that's just time/reading and observing.
sometimes guy's like bill and myself forget about typing this kinda stuff up, we just learned it as we went along.
heck it took me 3-4 years of reloading to have a clue what a meplat or an ogive was.
I had no clue about what they done. [shrug]
even when I found out what they were I couldn't/didn't ask anyone I really knew about them.
kinda sucky as I spent most of my youth hanging out at gun clubs and gun shops.
it wasn't until the late 70's early 80's when I started hanging out at Parkers gun-smithing shop that I started to really learning anything about how things worked.
and none of it really helped with this cast stuff.

[MtGun44]

Yeah - I think we probably should plan out a few basic intro type of posts,
and then get them circulated behind the scenes for some correction, expansion
and consensus bulding and then publish them with the intent of being
useful to the newbie. I did one on 9mm just because we were getting SO
much repetitive traffic on that one PITA cartridge - which I have never had
a bit of trouble with. So, I tried to put out a list of how I would go about
setting up for a new 9mm with boolits. Turned out to be useful, so maybe
we need a few more of them.

Bill

[tazman]

I would love seeing a sticky or even just a regular post that described in detail how to build a load with a new powder.
Details would include signs relating to overpressure and underpressure as well as feeding issues.
I looked at all the stickies yesterday. There is really nothing related to this topic. With all the great experience available on this site, such a thread could very well be definitive.
I have loaded for over 30 years but have never needed to build a load from scratch(without guidance from a manual) before this year. Mostly I didn't know where to begin.
I got away with it because I started way light on charge weight. Could have been really bad though, as I didn't know what the pressure signs were. No experience and no articles to inform me.

That 9mm sticky helped me avoid a lot of problems. Thanks again for that.