OAL for accuracy

[MTgrizz]

I am new to pistol reloading. I have reloaded a lot of ammo for bolt action rifles. The biggest gains in accuracy I saw in rifle ammo was loading the bullet out as close to the rifling in the barrel as possible without actually contacting it. I assume the same thing holds true for a pistol.

I realize that bullet shape has a lot to do with it, but what oal do most of you use in your XD's to gain accuracy and still fit in the mag and function? I obviously wont be decreasing oal below the recommended load data due to the potential for increasing pressure.

I have loaded a few rounds for my XDm 40 4.5" that are fairly accurate (probably more accurate than I can shoot them) but I can probably do better. Everything I have loaded so far has been at 1.125".

[Mercmar]

I load a lot of rifle and handgun ammo. I use the Hornady tool for determining o.a.l. for my precision rifle loading. I load pistol ammo so that it feeds well. I don't believe you'll notice a measurable difference in accuracy in handgun reloading, based on o.a.l.

[agalindo]

+1 on Mercmar's comment.

[57K]

Depending on the bullet style, 1.125" is probably a good OACL. If I were loading for only 1 9mm pistol I would find the max. allowable OACL where the bullet just touches the lands with a specific bullet and then shorten that OACL by .005" like you'd do in rifle reloading. Let me mention this also, all of my jacketed loads use JHP bullets. I don't use FMJ or plated. For economy, I just use cast lead.

Since I have multiple 9mm pistols with both long and short throats, I tend to use 2 different OACLs for JHPs. I've been doing it this way for a number of years with very good results and the OACL recommendations come from Vihta Vouri's metric OACL recommendations. For pistols with long throats like SIG, Glock and Ruger, I use 1.142"/29mm. For pistols with short throats like XD/XDm, some S&Ws and CZs, I use 1.122"/28.5mm. This has worked very well but you still need to establish the max. allowable OACL for your specific pistol with the specific bullet you intend to use.

And, welcome to the forum from Texas.

[fredj338]

Originally Posted by Mercmar

I load a lot of rifle and handgun ammo. I use the Hornady tool for determining o.a.l. for my precision rifle loading. I load pistol ammo so that it feeds well. I don't believe you'll notice a measurable difference in accuracy in handgun reloading, based on o.a.l.

^^THIS^^ In a high dollar match pistol w/ custom throated bbl, adjusting OAL might get you some measureable accuracy benefit, but not much. In production guns, probably nothing. Consider that most 38sp are more accurate than their shooters @ 50yds & the wc bullet is waaaaay far from the lands.
Even in rifle loads, adjusting OAL is the last thing I do to tweak a load. The bullet & powder combo are more important.

[szhttm]

For the XDm 40S&W, the most common OAL used by competitors is 1.145. The maximum length you could try is 1.150. After that, I believe you will encounter issues with reliable feeding of the ammo because the ammo will be rubbing on the inside of the magazine.



Good Luck And Be Safe!!!

[57K]

MTgrizz, sorry, I was talking about 9mm where there is much more variance in chamber lengths. Various brands of .40 S&W chambered pistols are much closer in chamber length due to the smaller variation in .40 S&W loads. For JHPs, I used the 1.125" OACL the most for JHPs, but have loaded from 1.120 - 1.130" due to different bullet styles and OACL recommendations. For cast loads I would use the OACL specific to the chamber and bullet style as I mentioned earlier and load bullets .005 - .010" off the lands. Not necessarily for accuracy but for safety and functioning issues. When cast bullets are loaded too long you can get out of battery issues. Too short and they may not function as well.

[MTgrizz]

After some trial and error, I cannot get my 155 gr SWC lead bullets to contact the rifling at all. The rounds get long enough that they will not fit in the magazine.

I loaded a couple long dummy rounds and dropped them in the chamber to see if I could get contact. The long rounds would not eject when I tried to clear the chamber. I suppose I can play around with a couple .001 and see what happens, but it doesn't look like there is much room to play with oal in my XDM.

[agalindo]

You don't to that with and XD. There's no reason for it. FYI you don't want a load that contacts the rifling it will cause excessive pressure. In RIFE rounds you want the to be a few thousands before contacting the rifling not contacting it.

[MTgrizz]

edit to remove double post