Inconsistent OAL Problems

[AngryBaker]

Hello everyone, I have been reloading for about 3 years now and have can honestly say I have never had a problem with my loaded ammo shooting accurately and reliably, however I have always had problems with OAL being inconsistent and it is driving me crazy.

First off I will list the equipment I am loading with. I am currently using an RCBS single stage partner press, Lee 3 die sets for all calibers, RCBS case trimmer, RCBS hand priming tool, Redding powder scale and a Hornady digital caliper.

The OAL is never too high or too low as to be dangerous or effect function, but when setting my seating die to achieve the desired OAL individual rounds vary by a fair amount. I currently load for 5 different cartridges and this has been a constant issue all calibers using a large variety of different bullets and brass.

As an example my go to 9mm range load is using 4.6 Gr of HP-38, CCI small pistol primers, Xtreme 115gr plated RN bullets, mixed once fired brass and a desired OAL of 1.135. This load works great in both my Glock 26 and Ruger SR9. When first seating bullets I will go through and calibrate the seating die with 5 primed and charged rounds. Once the seating die is adjusted and locked down I then begin to to seat bullets in the remaining cartridges.

When measuring individual cartridges during the seating process I am seeing OALs both longer and shorter than the desired OAL. This difference in OAL can be +/- .015. With the average being about +/- .005. Using this load is an example I could see measured OALs from 1.120-1.150 and anything in between. I have seen similar results across my .223 REM, .243 WIN reloads and to a lesser effect on my .44 mag/spl reloads.

This has been bugging me for some time and I really want to get this corrected. Maybe I am just blowing this way out of proportion. Any help or suggestions you all can offer are greatly appreciated.

 

[jwrowland77]

For rifle, your best bet is to measure to the ogive. I'll guarantee you, your base to ogive measurement will be the same (assuming you measure consistently with same pressure).


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[fouled bore]

I have had that issue if my primers were not getting seated all the way in.

 

[tcoz]

What you're seeing is normal. Seating dies contact & seat the bullet from the ogive and not from the tip. If you were to take your loaded rounds and measure the ogive to base length using a bullet comparator you'd find that measurement to be the same and that's the important measurement anyway. Ogive to bullet tip measurement can vary from one bullet to the next so if you're measuring tip to base you'll get different results.

 

[joneb]

mixed once fired brass

I have had that issue if my primers were not getting seated all the way in.

I primed some Win. 9x19 trimmed to 18 mm with CCI 500 all of the primers were above the case head. The loads all fired, The pockets are shallow and Walkalong recommended this; http://kmshooting.com/primer-tools/...stol-rifle-primer-pocket-correction-tool.html
If you have high primers its hard to get a accurate COL.

 

[macgrumpy]

tcoz is absolutely correct.

Bullets vary in overall length by several thousandths of an inch, some will vary by as much as .015". The seating die contacts the bullet at some point below the tip, not necessarily the ogive but somewhere between the ogive and the tip. The exact contact point varies depending on the bullet and the manufacturer of the die. Regardless, measuring the OAL of a cartridge is not a dependable way to obtain consistency, measuring at the ogive is.

 

[X-Ring]

can honestly say I have never had a problem with my loaded ammo shooting accurately and reliably

Then do yourself a favor and stop worrying about it.

 

[fouled bore]

I primed some Win. 9x19 trimmed to 18 mm with CCI 500 all of the primers were above the case head. The loads all fired, The pockets are shallow and Walkalong recommended this; http://kmshooting.com/primer-tools/...stol-rifle-primer-pocket-correction-tool.html
If you have high primers its hard to get a accurate COL.

These were 380 Win brass, I have heard other people having the same problem. I got a Lyman Tool and cut the pockets deeper and that took care of it. My COL is normally with in .005 if I am using a good quality bullet. I picked up some low quality bullets for plinking and also had an issue with COL varying a lot.

 

[HKGuns]

What you're seeing is normal. Seating dies contact & seat the bullet from the ogive and not from the tip. If you were to take your loaded rounds and measure the ogive to base length using a bullet comparator you'd find that measurement to be the same and that's the important measurement anyway. Ogive to bullet tip measurement can vary from one bullet to the next so if you're measuring tip to base you'll get different results.

This is the accurate answer. You will absolutely NEVER get consistent OAL measuring this way, no-one does.

Keep loading, you are doing fine.

 

[Blue68f100]

When measuring individual cartridges during the seating process I am seeing OALs both longer and shorter than the desired OAL. This difference in OAL can be +/- .015. With the average being about +/- .005. Using this load is an example I could see measured OALs from 1.120-1.150 and anything in between. I have seen similar results across my .223 REM, .243 WIN reloads and to a lesser effect on my .44 mag/spl reloads.

You should not be getting more than ±0.005" with quality bullets, or even cheap ones. The low and high ones may be due to setting friction damaging the bullet. I would take a close look at your seating stem. If your contacting high on the bullet nose this can damage the bullet giving you the large swings. Try to contact lower down and you will get a more consistent OAL. Lee and other offer a custom seating stem, cheap. Or do what I do if I have one marking the bullet badly. I chuck it up in my drill press and go after it with some sand paper backed with a rod and reshape it, then polish it out.

A cheap way to get a measurement on the ogive is use a hand gun cartridge that contacts the bullet where your seating stem is contacting the bullet. Use this for a reference as to how much bullet you have seated in the case. With some powders and calibers combo a little as 0.020" bullet setback can put you into some dangerously high pressure. Where k-booms happen if your at max load.

 

[spitballer]

Speaking strictly as a small-time reloader for a bolt rifle, most of my OAL inconsistency has been the result of hard brass. Hardened brass just can't be counted on to stretch consistently, especially if it has a varying wall thickness. However, if the necks have been turned I've been able to make use of even the toughest brass by sizing it just tight enough to hold the bullet. Again, this is for a bolt rifle: autoloaders with crimps are another ball game.

 

[Ole Joe Clark]

I agree with the guys above, quit worrying about it and shoot the suckers.

However, if you look at the case head, especially on pistols, you will find that a lot of them are not flat and then you are measuring to the high point on the head. I never check loaded rimmed pistol cartridges length, I check 40 cal and such, but then my real quality check is the "plunk" test, if they pass they get shot, if they don't I run them through the taper crimp die again, and that solves the problem on 99.875% of them.

Have a blessed day,

Leon

 

[warhammer]

Glad I found this thread. I've had similar things and always wondered if it was due to how i moved the loading arm or whatever.

I've even resorted to sloooowly loading the bullet and measuring along the way.

gonna load some up "regular style" and see what i see!

 

[AngryBaker]

Thanks for the help folks. I greatly appreciate it. Glad I am not alone in this and I know what is going on now.

 

[rcmodel]

Sometime if you ever get another chance.

Measure a box of factory loads.

You will think you are an expert reloader with what you are getting.

rc