9mm oal

[hollywood63]

I was loading some 115 gr acme lead coated bullets with 4.9 CFE with a oal 1.100. After loading 50 I switched to a xtreme plated bullet with the same specs. After I was done I noticed I screwed up and loaded 124 gr. which call for a oal of 1.150. So you think they would be safe or am I pulling them? :banghead::banghead:

 

[Lethal rx7]

I load my 124gr rn at 1.12

 

[cheep]

I load my 124grn Extreme to 1.10", don't worry about it.

 

[gamestalker]

OAL aside, wouldn't there be a problem using data for 155 gr. with a 124 gr. bullet?

Or did you adjust the powder charge for the 124's, just not the OAL?

GS

 

[MajorMagnetic]

Hello...if you look at the load data in your book, it will probably tell you the 9mm OAL is crucial. Just a few thousandths will raise the pressures very quickly. At lease all my books tells me that. There's always some variance, depending on the brass. I don't mind going longer, but when you go shorter, the 9mm is extremely sensitive to that, as far as pressures go. Check your reloading book and see what it says.

HTH....
MM

 

[GJSchulze]

If the 124 gr bullet has the same profile as the 155 bullet, then loading it at the same OAL will result in more case volume which will reduce pressure. Heavier bullets require less powder, so the same powder charge with a lighter bullet is actually a reduced charge.

 

[gamestalker]

I fully realize that a lighter bullet with the same charge produces lower pressures, but that was my point. If the weight difference between the two bullets is significant, which 155 gr. to 124 gr. would certainly qualify, it could easily create a squib. And friction is going to be a bit greater with the 124 gr. plated bullet, compared to a lead bullet, so this could create a problem also. Think of it this way, would you use the same data for a 124 gr. bullet for a 155 gr. bullet?

And yes, as far as OAL, 9mm is one of the highest pressure and oal sensitive AL cartridges around. Speer #10 states that pressures more than doubled with a developed load producing a normal 28,000 cup, and jumped to 62,000 cup when the oal was deliberately reduced by only .030".

IMO, anytime you change a component, and especially one this significant, the load should be reworked. I don't have any experience with either the bullets or powder the OP is using, but it might not be a bad idea to locate some data that's relevant to the bullet weight, profile, and construction. Might save him the frustration of removing a stuck bullet from the barrel.

GS

 

[hollywood63]

OAL

Sorry guys had fat fingers it was 115 gr that I was loading and used 124 without adjusting the OAL I checked the bullet length and the 115 is .552 and the 124 is .582 .

 

[grogetr]

As stated earlier .040" will increase pressure quite a bit. On Hodgdon site 4.9 is the start charge for plated 124 gn but the shorter length will increase pressure way more than what the max charge pressure with the suggested oal produces.

 

[LeftyTSGC]

I load my 124gr Xtreme at 1.100 for my specific handgun, i have used this OAL with W231, Longshot, Power Pistol and now BE-86. The powder companies show you what they used to determine their loads. It is not a set in stone parameter. If you use all of the same components then yes it has more relevance.

They used a 124 GR. BERB HBRN TP, need to measure and see how close to the Xtreme that comes. As mentioned before, you need to start loading at the minimum and work up from there.

Your overall length can be anything that works in your handgun, hopefully you did a plunk test and found your specific pistols working oal. Then you need to work up the load. that is what i did for all of the poweders listed above at the SAME OAL.

I am not saying it doesnt matter, but do not get hooked on what the book states, use it as a start reference and relate your loads to it. Add and subract as needed, test and verify. Then go Shoot.

 

[Potatohead]

Data wise, Im not sure because I dont have my loading stuff with me..OAL wise, with 9mm Ive safely loaded from 1.10 to 1.155..starting low and working up of course.

 

[gamestalker]

Ok, so since the conditions are some what contrary to the original scenario, in that, we are now considering using a heavier 124 gr. bullet, with data intended for the lighter 115 gr. bullet. Even more so concerning, is that these are bullets of two different profiles and construction. This condition most certainly produces an unpredictable pressure result.

If in fact, the 124 gr. projectile produces less internal case volume when seated to plunk test acceptably, then most certainly pressures will be higher. OTOH, if case volume is increased it can be considered that pressures may be lower.

Bullet profile, variations in bullet construction, obvious weight differences, and the likely data conflict all concerned, and we have a very unpredictable pressure result. IMO, I wouldn't even consider shooting these. They should be pulled and proper reloading protocol followed.

For those who are new to this hobby, and that are following this thread, this is not the recommended SOP for this hobby, and certainly not when working with a high pressure oal sensitive cartridge, such as 9mm is.

GS

 

[Steve C]

I was loading some 115 gr acme lead coated bullets with 4.9 CFE with a oal 1.100. After loading 50 I switched to a xtreme plated bullet with the same specs. After I was done I noticed I screwed up and loaded 124 gr. which call for a oal of 1.150. So you think they would be safe or am I pulling them?

You are at the start load of Hodgdon's data. Personally I'd shoot a few and look for pressure signs but wouldn't expect any.

 

[LiveLife]

lead coated bullets with 4.9 CFE with a oal 1.100 ... 124 gr.

Since OP loaded 124 gr coated lead bullets at shorter 1.100", I would reference the more conservative load data for 125 gr FMJ @ 1.090" which shows 5.1 gr as max charge and lower start/max charges than load data for HBRN-TP loaded at longer 1.150" - http://www.hodgdonreloading.com/data/pistol

124 GR. BERB HBRN TP CFE Pistol OAL/COL 1.150" Start 4.9 gr (1,006 fps) 27,300 PSI - Max 5.5 gr (1,120 fps) 33,800 PSI

125 GR. SIE FMJ CFE Pistol OAL/COL 1.090" Start 4.6 gr (1,009 fps) 26,900 PSI - Max 5.1 gr (1,118 fps) 33,000 PSI

hollywood63, I would check the finished rounds for bullet setback by feeding/chambering from the magazine without riding the slide. If they don't experience bullet setback, I would probably shoot them but if you measure significant bullet setback (more than a few thousandths), I would pull the bullets.

Regards to bullet seating depth, it's the "chambered" OAL/bullet seating depth that matters more than OAL/bullet seating depth before being chambered.

As to OAL/COL, simply following published lengths may not be ideal for your pistol/barrel. You should determine the Max/Working OAL BEFORE you conduct your powder work up from start to max charges specific to the bullet you are using (When I cannot find the load data specific to the same bullet type, I use the most conservative load data for my initial powder work up) - http://www.thehighroad.org/showthread.php?t=506678

 

[Zendude]

And yes, as far as OAL, 9mm is one of the highest pressure and oal sensitive AL cartridges around. Speer #10 states that pressures more than doubled with a developed load producing a normal 28,000 cup, and jumped to 62,000 cup when the oal was deliberately reduced by only .030".

GS

Wow, i didnt realize it was that sensitive. I'm definitely going to get my OAL exactly right when making 9mm.

 

[gamestalker]

Oh ya, 9mm can get into some very excessive pressures real quick and in a hurry if we don't develop in the correct order. Many fail to realize that the 9mm operates at pressures similar to full house .357 mag.. But the best way, correct way to avoid a situation, is to always develop the powder charge around a designated functional oal, not the other way around.

GS

 

[hollywood63]

Thanks guys pulled them and redid. Good lesson to pay attenion