This is my first time(ever) reloading. So bear with me...

Im attempting to reload 10mm for the first time.
I'm using RCBS 3 dies set on single stage turret press.

and Im having little issue trying to figure out few things.
According to my Lyman 49th edition hand book, SAMMI spec dimension for 10mm is:

Case length:0.992"
Case Mouth:0.423"

My once fired case is uniformly oversized(naturally), and I put 100 empties through resizing die last night(how de-primer "pop"s the spent primer was interesting)
Because its my first time, I measured every single one of resized cases, and none of it matchs the number above.
After resizing, case mouth were 0.416"+.001~.002".
I figured this wouldn't matter, as it will be flared at next station, and once bullet is seated, i'll take the measure again.

But my case length were avg. of 0.986". Its anywhere from smallest of 0.982 to largest of 0.988".
And none came close to 0.992" as my book says.
Is difference of 0.006" something significant that I need to worry about?

Thanks, and sorry for possibly a stupid question

I believe yr .992 lenght is the MAX lenght your looking at...due to case edge fit into chamber.

Most of my brass av about 986 to 988.

BTW new brass from Starline  = 0.984 - 0.991 O.A.L.


Edit;  sammi specs I just looked at call for .992 - .010 (for yr max - min )

What type of gun, what bullet head/powder/etc ?

Couple of things, If you don't have , see if you can beg,borrow,steal, buy if u must the ABC's of reloading.. read it several times!

Watch the OAL for the completed bullet , go with book start loads with first set of rounds... if no powder min listed but only max, lowering the charge by 10% would mostly be ok.
Build up your loads a set amount and test before making many....

Most of all, ASK questions. There are smarter people here when it comes to reloading and they'll freely give advice.

Good questions...many good responses already.
Case length:0.992" Maximum length they will get shorter with use and I have never had to trim any. 
Case Mouth:0.423" should be considered max with respect to the seated bullet I like to add just enough taper crimp that sets the very edge of the case mouth 0.4220"-0.4215" (my RCBS taper crimp die (older 10mm only from 1990) will show a slight shine on the case mouth edge at these measurements)  The most critical measurement is the section near the start of the extractor cut and slightly above, this is where the "SMILES" and bulge starts to present an issue.  Pass through sizing is the only way to reach the entire section that standard dies can't.

I usually seat all my bullets to 1.2500" but most guns will work out 1.2650" some even more...Some bullets are even seated down to 1.2400" because of the nose shapes.  A Cartridge case gauge will help with pass or fail fits.

Quote from: tommac919 on August 10 2014 12:11:23 PM MDT
What type of gun, what bullet head/powder/etc ?

The case is mix of Hornady, and Federal Eagle. All fired once.
Gun is RIA 1911 in 10mm with full support(wanted DE for the longest time. And I'll likely get it in future. But I wanted one with full case support).

Recipe for this load.

BlueDot 8.1gr
CCI 300 primer.
Hornady 180gr XTP #40040
OAL 1.250"

According to book, this should give me around 950fps. I know its sort of weaker side of things, but I figured I'd start min suggested starting load. I'll load 5 this. Then slowly increase the charge up to about 9.5gr, and shoot for around 1100fps?
Being that this I first time, I feel like I should start slow...

Getting to know and understand your equipment, with special interest of your scale's repeatability, is key to your trust and safety.  Blue Dot is a great powder and it burns cleaner at the upper spectrum.
Best regards!

Quote from: Mity2 on August 10 2014 02:54:40 PM MDT

Quote from: tommac919 on August 10 2014 12:11:23 PM MDT
What type of gun, what bullet head/powder/etc ?

snip
Recipe for this load.

BlueDot 8.1gr
CCI 300 primer.
Hornady 180gr XTP #40040
OAL 1.250"

According to book, this should give me around 950fps. I know its sort of weaker side of things, but I figured I'd start min suggested starting load. I'll load 5 this. Then slowly increase the charge up to about 9.5gr, and shoot for around 1100fps?
Being that this I first time, I feel like I should start slow...

Always better to start slow and work up...
I know for a fmj fp 180 grain the most accurate load for my stock g20 comes in around 10.2-10.4 gr of bluedot which is middle+ ( 11 being book max ) As mentioned, BD seems to burn cleaner in the upper range.
The biggest caution as Shadow mentioned can be yr scale and/or powder drop... as you get closer to max load.  I find my lee powder drop when running good is only +/- .2 grs.... so you can see problems can occur if running at upper limits.

I recommend getting a Lee Factory Crimp Die.  I had the same issue with some brass being below the trim to length, which makes uniform crimps hard to do. The Lee FCD don't care. I've had mine a short time, but after several batches, I'm very happy with it. Crimping is one of those things in handloading that's tricky for beginners. The Lee makes it almost fool proof.

Well, I loaded up 10 try out rounds.
5 of 8.1gr, and another 5 of 9.0gr(although, it ended up being 8.8gr. I need to work on my powder dropping technics...)
I actually had a issue with not being able to set up my seating dies correctly. And very first 2 rounds I loaded was really bad.
My friend, the reloader had to come over and help me(or more less he did it, and I watched) set up my seating dies.
(something about my taper crimp dies were too low - or screwed in too much, and it was crimping the round before bullet had seated)



So after my friend set up the dies correctly, I made first 5 rounds. He, the reloader felt that the 8.1 was too light. So he adjusted the powder drop and i made another 5 with 9.0gr of Blue dot

OAL was set at 1.255"

It was getting dark. So we just went out to shoot it, just shoot it.
8.1gr IS too light. gun felt like shooting 9mm 1911.
9gr is still not really hot in anyway. Felt like shooting .38Super.

Its a small start. But Im so excited that those 10 rounds functioned.
reloader buddy and I feel that may be I should try somewhere in 9.8gr range next time.

Im gonna do some research and try some more reloading tomorrow.

Oh we didn't chronograph it, or even really aim at anything.
But I bet FPS was low 900 range...

But they all fired, ejected, and loaded the next round

You will find that if you seat the bullets to depth without any crimp being applied will be your best option and then re running the cases finalizing the taper crimp.

I use a 1/8" thick washer under the seater/taper crimp die while seating the bullets to depth.  This raises the die so no crimp is applied, but the seater stem is adjusted for bullet depth...it needs to be backed off so it doesn't touch the seated bullets when I remove the 1/8" spacer so I can run the cases back to taper crimp to finish them.

The use of the spacer washer keeps me from having to re adjust the locking ring to maintain taper crimp setting. 

You can find these spacers at Midway USA; http://www.midwayusa.com/product/189290/redding-die-spacer-kit?cm_vc=ProductFinding

Redding Die Spacers allow for quick compensation for case length, partial resizing, or to make a no-crimp adjustment without the need to move the locking rings. Kit contains a no-crimp or partial resizing spacer (.062), a 44 Special/44 Magnum spacer (.125) and a 38 Special/357 Magnum spacer (.135). Fits all 7/8" - 14 Dies.

Technical Information

Kit Contains:
No-Crimp or partial resizing spacer (.062)
44 Special/44 Magnum spacer (.125)
38 Special/357 Magnum spacer (.135)
Notes:
For use with combination die sets and in all 7/8-14 reloading dies.
Kit alllows you to quickly compensate for case length or make a no-crimp adjustment without the need to move the lock rings.

As an example of my use for these spacer rings, I have a RCBS 9mm die set, I use the expander die set for the proper 9mm case expansion to accept the bullet, using one 1/8" spacer under this die raises it for proper case expansion on 357Sig and using two spacers raises the die a 1/4" and will provide proper expansion for my 9x25Dillon cases without having to adjust the locking ring adjustment!  Pretty neat and sweet!

Right there with Shadow.  Seat and Crimp in separate steps.

And, keep in mind when crimping you you aren't cranking on them.  You want just enough crimp to take the flare back out.  This isn't a roll crimp for a heavy loaded 454 Casull.  Most new reloaders over-crimp, especially on taper crimp rounds like 10mm.

In the pictures you posted is is clearly evident, why seating and crimping should be done in separate steps.  This one in particular shows the bullet is not completely seated to proper depth, when the crimp was being applied.  The casing started to close up, the casing grabbed the bullet's jacket material and then the casing started to buckle as a result.  While it is possible to make the cartridge in one step, they may not even show things that are happening, grab the bullet and see if it will turn in the casing.  Push (against a strong surface) / pull the bullet looking and feeling and even measure for any movements. The slightest discrepancies can cause you feeding reliability issues.



By seating without crimp being applied you get straighter bullet seating, better casing to bullet tension, then when you apply the closing crimp, it tends to lock the bullet in place better, as the case mouth closes toward the bullet that isn't moving.  Sometimes when you check by pulling cartridges apart, you can see a slight crimp ring on the bullet's surface, this is not a bad thing or too much crimp, because the crimp pushed straight inward to lock it in place.

Quote from: The_Shadow on August 11 2014 09:48:53 AM MDT
snip...  While it is possible to make the cartridge in one step, they may not even show things that are happening, grab the bullet and see if it will turn in the casing.  Push (against a strong surface) / pull the bullet looking and feeling and even measure for any movements. The slightest discrepancies can cause you feeding reliability issues.

For my 10mm I run a Lee pro 1000 press ... since its has only 3 dies, the taper / seating are done in same time. Yes, a pain to set up and get right, took about 10x to get it right.
Most important is running the "push" test.  Push the completed bullet against the bench and make sure the head stays in place.
A good caliper also goes a long way.
(BTW.. I wouldn't recommend them as they can be 'finicky' to say the least. I find it's a one bullet press and doesn't like changes!)

Quote from: The_Shadow on August 11 2014 09:48:53 AM MDT
In the pictures you posted is is clearly evident, why seating and crimping should be done in separate steps.  This one in particular shows the bullet is not completely seated to proper depth, when the crimp was being applied.  The casing started to close up, the casing grabbed the bullet's jacket material and then the casing started to buckle as a result.  While it is possible to make the cartridge in one step, they may not even show things that are happening, grab the bullet and see if it will turn in the casing.  Push (against a strong surface) / pull the bullet looking and feeling and even measure for any movements. The slightest discrepancies can cause you feeding reliability issues.



By seating without crimp being applied you get straighter bullet seating, better casing to bullet tension, then when you apply the closing crimp, it tends to lock the bullet in place better, as the case mouth closes toward the bullet that isn't moving.  Sometimes when you check by pulling cartridges apart, you can see a slight crimp ring on the bullet's surface, this is not a bad thing or too much crimp, because the crimp pushed straight inward to lock it in place.

Ya you pretty much hit the nail in the head.
My friend adjusted the dies. It took him several tries. But I think its running good now.
I loaded another 20 rounds - 10 with 9.3gr blue dot, and another 10 with 9.8gr.
I think it look good.




OAL is 1.255". is that too much?

You should be good to go at the 1.2550".  Yes they look a lot better, if the bullets remain tight in the casing.  If the case mouth is 0.4230" or less they should function reliably.  I place my test cartridges in bank envelopes or bags clearly marked with the info and even take notes at the firing test, then place everything back inside and do a study when I get back home.

Good luck with your testing!