10 mm oal

PowerPro · July 5, 2009, 02:06 PM

I have 2 reloading manuals the states that a 10 MM OAl is 1.260. I bought a Dan Wesson Cbob classic that will not chamber the 1.260, the slide will not close. A friend gave me some factory Winchester 165 grain hollow points to try. I mike’d them at 1.250 they chambered and fired perfectly. My Glock 29 will eat the 1.260s all day long. What gives????

Greg

**Unclenick** · July 5, 2009, 02:35 PM

Welcome to the forum.

Tight chamber or short throat or bullets with bearing surface that is long relative to the ogive (the part that curves in toward the tip). Keep in mind the lengths given in the manuals are SAAMI maximums for any bullet shape. That maximum is just to insure a bullet will fit in a SAAMI compliant magazine. Many bullets with blunt shapes have to be seated shorter. As far as pressure goes, it is how far the base of the bullet goes into the case, not the COL (aka, OAL, COAL) that matters. Just follow the bullet maker's recommendation in that regard. When you copy a load from a manual, use the same brands of brass and primer as well as the recommended COL and powder charge. Changing any of those variables can change pressure. If you can't make a match, lower the powder charge 10% and work up to it in small steps, watching for pressure signs. Stop when you've got something accurate that functions the gun reliably.

PowerPro · July 5, 2009, 03:01 PM

Unclenick,

Thank you for the information and the welcome. I've been reloading for 5 years and feel like I still don't know anything. I never load to the max, I have to much money invested in my pistols to have a ka-boom. I've used 3 different powders so far, Blue dot, Power Pistol, and unique in my 10 MMs and and the later 2 in my 45 ACPs. I load low and slowly work my way up to find what shoots best. Even thought unique is a pain in my RCBS powder thrower I seem to get the best groups from it in both calibers. I am ready to move on to different powders but I like to study the powder before I try it. That is one of the reasons why I joined this fourm. Thanks again.

Greg

Sevens · July 6, 2009, 12:51 AM

I like Power Pistol in 10mm as it meters well and works well with a moderate charge. I'm currently loading 150gr Nosler JHP's pushed by 9.4gr Power Pistol and loaded to 1.246" COAL. These feed and fire 100% without so much as a hiccup in my G29. It gobbles 'em up and begs for more all day long.

Another powder you might consider trying is Accurate #7. It meters as well as any powder ever made.

Alleykat · July 6, 2009, 07:30 PM

1.250", just like my .45ACP reloads.

TheGreatDane · July 19, 2010, 10:45 AM

Hello Everyone,

I have a 10mm OAL question, therefore I've resurrected this thread (thanks search button).

I'read max 10mm OAL is 1.260. After loading up 100 rounds last night, I discovered my OAL slowly grew towards the end, resulting in the last 20 exceeding 1.260 by about .005.

My question is: provided that these rounds (in excess of max OAL) chamber and allow the slide to lockup in-battery, will there be any danger in firing 'em off?

I've already tried further seating, but the taper crimp I put on 'em isn't allowing it (.423). I'd really hate to pull 'em and start over. Next time I'll be more mindful of OAL before crimping.

July 5, 2009, 02:06 PM	#1
PowerPro Junior Member Join Date: July 3, 2009 Posts: 2	10 mm oal I have 2 reloading manuals the states that a 10 MM OAl is 1.260. I bought a Dan Wesson Cbob classic that will not chamber the 1.260, the slide will not close. A friend gave me some factory Winchester 165 grain hollow points to try. I mike’d them at 1.250 they chambered and fired perfectly. My Glock 29 will eat the 1.260s all day long. What gives???? Greg

July 5, 2009, 02:35 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Welcome to the forum. Tight chamber or short throat or bullets with bearing surface that is long relative to the ogive (the part that curves in toward the tip). Keep in mind the lengths given in the manuals are SAAMI maximums for any bullet shape. That maximum is just to insure a bullet will fit in a SAAMI compliant magazine. Many bullets with blunt shapes have to be seated shorter. As far as pressure goes, it is how far the base of the bullet goes into the case, not the COL (aka, OAL, COAL) that matters. Just follow the bullet maker's recommendation in that regard. When you copy a load from a manual, use the same brands of brass and primer as well as the recommended COL and powder charge. Changing any of those variables can change pressure. If you can't make a match, lower the powder charge 10% and work up to it in small steps, watching for pressure signs. Stop when you've got something accurate that functions the gun reliably. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

July 5, 2009, 03:01 PM	#3
PowerPro Junior Member Join Date: July 3, 2009 Posts: 2	10 mm oal Unclenick, Thank you for the information and the welcome. I've been reloading for 5 years and feel like I still don't know anything. I never load to the max, I have to much money invested in my pistols to have a ka-boom. I've used 3 different powders so far, Blue dot, Power Pistol, and unique in my 10 MMs and and the later 2 in my 45 ACPs. I load low and slowly work my way up to find what shoots best. Even thought unique is a pain in my RCBS powder thrower I seem to get the best groups from it in both calibers. I am ready to move on to different powders but I like to study the powder before I try it. That is one of the reasons why I joined this fourm. Thanks again. Greg

July 6, 2009, 12:51 AM	#4
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	I like Power Pistol in 10mm as it meters well and works well with a moderate charge. I'm currently loading 150gr Nosler JHP's pushed by 9.4gr Power Pistol and loaded to 1.246" COAL. These feed and fire 100% without so much as a hiccup in my G29. It gobbles 'em up and begs for more all day long. Another powder you might consider trying is Accurate #7. It meters as well as any powder ever made. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

July 19, 2010, 10:45 AM	#6
TheGreatDane Member Join Date: November 18, 2008 Posts: 29	10mm Exceeding Max OAL Hello Everyone, I have a 10mm OAL question, therefore I've resurrected this thread (thanks search button). I'read max 10mm OAL is 1.260. After loading up 100 rounds last night, I discovered my OAL slowly grew towards the end, resulting in the last 20 exceeding 1.260 by about .005. My question is: provided that these rounds (in excess of max OAL) chamber and allow the slide to lockup in-battery, will there be any danger in firing 'em off? I've already tried further seating, but the taper crimp I put on 'em isn't allowing it (.423). I'd really hate to pull 'em and start over. Next time I'll be more mindful of OAL before crimping.

July 6, 2009, 07:30 PM	#5
Alleykat Junior member Join Date: July 26, 2007 Posts: 3,668	1.250", just like my .45ACP reloads.