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Inconsistent OAL, from mixed brass?


jmoney
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Loaded a small batch and noticed oal ranging from 1.15 to 1.30. I pulled open my box of last reloads I've been using for awhile and they range from 1.15-1.28. Checked the shellplate, it is just loose enough to rotate. I have the right seater for JHPs. I am wondering if this is the result of two things. (1) I use very random mixed brass, whatever I get cheapest (2) some of it needs to be swaged so when I find one, I pull it off the line and continue on meaning that I'm seating some without a full load on the plate. Is this likely the issue? The rounds have been pretty accurate in IPSC and the defensive handgun stuff I do so should I really be concerned?

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Mike your mixed brass and you will most probably note that much diffrence in the lengthof the unloaded, sized cases. You will also probably note that there are variances in teh extractor groove and teh case head thickness which both could cause a variance of your OAL.

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how does mixed brass change oal.

if the dies are in a fixed location and the shell plate has the same amount of stroke , all rounds would be the same regardless of headstamp.

the only thing that could change is the bullet ogive. but if the seating stem is directly on the nose all rnds should be the same.

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One of the bigger problems with different length cases is the fact that it varies the amount of crimp, so you have a variance in the resistance to setback, possible difference in velocity and possibility of damaging plating on plated bullets.

I just think it's better to sort by brand and load all one brand in each batch of ammo. This will depend on your total supply of brass in any one caliber, of course.

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One of the bigger problems with different length cases is the fact that it varies the amount of crimp, so you have a variance in the resistance to setback, possible difference in velocity and possibility of damaging plating on plated bullets.

I just think it's better to sort by brand and load all one brand in each batch of ammo. This will depend on your total supply of brass in any one caliber, of course.

I do agree with the crimp.
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how does mixed brass change oal.

if the dies are in a fixed location and the shell plate has the same amount of stroke , all rounds would be the same regardless of headstamp.

the only thing that could change is the bullet ogive. but if the seating stem is directly on the nose all rnds should be the same.

Good question, and I'm not sure I can answer it to a specific degree.

I do know that mixed brass can result in inconsistent velocities (often still within acceptable margins, though). As for length, I don't think so. That's decided by the press. The greatest variable is the solidity of the base platform -- the shell plate. If it wanders, so does the length of the cartridge.

How much is variance is too much? Better yet, how does the ammo run? Any malfunctions?

We're not shooting Bullseye. It's USPS/IPSC. 1-1/2" versus 1" at 15 yards is not enough to worry about.

Some varience should be expected if the shell plate isn't tightened to spec.

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lots of fun to be had with reasons for the variations.

the shape of the bullet and the shape of the die pressing it in will give you some variation.

I have a lee die that gives me varying OAL with plated bullets

and a RCBS(I think that is the brand) die that has no such problem.

I get consistent OAL from both when pressing FMJ.

I read some where that one must match the die to the bullet being pressed

for consistent OAL. and presumably consistent target shooting...

that advice was about making rifle ammo.

It did send me looking for a different bullet seating die when I

found the OAL was not to my liking.

miranda

Edited by Miranda
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Been following this thread with some interest. Seems somebody has "donated" some different brass to my usually sorted Winshester and Federal supply. Was loading this morning, and noticed some very hard to resize cases. When loaded said brass produced OAL in the 1.122 range. My usual is 1.110. Checked Win and Fed OALs and all were 1.110 to 1.112. IMI and VZ is consistantly 1.115 to 1.122. Guess the best way to tell on your press is to load 25 or so of all one brand, and measure. Then load 25 or so mixed and measure. Maybe the press, but today's experiment would indicate that it's more the brass and resizing resistance... Thanks for the heads-up Dwight!

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there are time when I find I am quite puzzled.

I went and looked at press designs and I am thinking the press is not going to flex

anywhere near as much as the case and the copper/lead bullet will.

In fact I am pretty darned sure that my turret press can crush a 9mm case.

so it is not the flex of the press causing the inconsistent OAL. the bullet and the case will flex more.

if inconsistent OAL is a problem you need to look at bullets for inconsistencies as well as the cases.

a press has the leverage to reshape both bullets and cases.

you may want to be sure you are driving the press to the end of the stroke as well.

of those three, the press is not the source of the flexing.

miranda

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I reload on a single stafe press and I can tell Winchester brass, and Speer brass from the other makes when sizing a batch. the winchester seems to fit tighter, but sizes very smoothly. The Speer brass hardly seems to feel like it is touching the die. Some of the European brass seems pretty hard to size and alomost feels "gritty" even those that have been cleaned first.

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All presses flex to some degree during the loading process. The compound linkage between the handle and the ram can produce incredible amounts of force including the force necessary to crush a casing, but the press body will flex. The more pressure, the more flex.

Dwight

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hohohohohohoho

if you can keep your head while all others are losing theirs then

you don't know what the problem is.

greetings,

Let me get this straight...

The range of the OAL in the original post was 1.15-1.28 (I assume inches.)

You are telling me that a lead/copper bullet and a brass case

are stout enough that they can cause a reloading press to 'flex'

about .13 inches when seating bullets?

If you have that kind of OAL issue,

the press could be broken or have an operational error. (and a darned clear problem)

You should look some where besides the press for the source of that 'flex.'

miranda

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I use MG 124 JHPS, they appear to be pretty well made. I shot about 400 rounds yesterday and the rounds are accurate out to steel silhouettes at 50 yds. Close range, I thought I was seeing some variation, I handed to gun over to a far superior shooter and he showed no accuracy issues with the rounds. When I say variation, I mean that we were shooting small sections of VTAC targets which present a very tiny 1"-1.5" acceptable shot range. Switching over to a small 2" steel plate (hostage taker) that flips from side to side of a steel silhouette revealed no accuracy problems. My main concern with varying OAL is safety, I'm reloading on a dillon 550b. I will continue to see if I can locate the source of inconsistency.

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Are you seating and crimping at the same station? If so, I think you are putting too much crimp too soon. I've seen other new reloaders have the same issue. Make sure you have enough bell, then make sure you are seating to the correct depth, then begin adjusting crimp. Also make sure you have the correct seating insert in your die. RCBS dies come with a few different inserts for different bullets. I'm not sure about other brands.

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Next batch I'm going to completely reset the crimp, the bullets come out of the seater at 1.15, the crimp did not visually appear to be too much, just enough to take the bell off. However, considering the variance I will try and completely reset that die and see if it isolates the issure

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Are you seating and crimping at the same station? If so, I think you are putting too much crimp too soon. I've seen other new reloaders have the same issue. Make sure you have enough bell, then make sure you are seating to the correct depth, then begin adjusting crimp. Also make sure you have the correct seating insert in your die. RCBS dies come with a few different inserts for different bullets. I'm not sure about other brands.

Check the inserts for sure. This gets a lot of new reloaders especially with 40 S&W.

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With mixed brass .005 variance is not bad, over that may be. Went through this last summer in 9mm minor.

The cure for me was a Lee sie set. I like Lee's first stage sizer as it sizes a little closer to the extractor groove

and a little tighter that other brands. Lee also has an excellent primer punch. Lee's seating die has a small knob on top for slight adjustments. Marking the knob with a sharpie makes for easier change over to other bullets.

The fix was sending a bullet to Lee, They made an insert that fits that bullet and that helped. I like to shoot heavier bullets usually

160 lead or a Frontier 147 plated for indoor. I had a machinest in the club make me a flat insert. That solved my OAL

problems. The flat insert only pushes on the tip of the bullet.

The 160 bullet mikes .356 to .357 so need to lube cases just a small amount of lube helps the bullet into the case

along with making the whole process easier on the brass, dies, press and operator. Check the belling/powder die for the

correct amount of bell.

The first stage sizer holds the bullet all crimp does is help the bullet feed into the chamber. To much crimp and accuracy

will suffer. Try loading rounds out in the 1.145 to 1.150 or as long as you can and they run in your magazines. More times than not you group will tighten. At present Lee sizer, Lee seater and Dillon crimp die. Have run Lee's U die in station one but have backed

up to a standard Lee sizer in 9mm. Using the U die in 40 S@W.

Loading on a 650 no swager so I spend a little time inspecting 9mm range brass. Standing them up on a table I'll look in

the case for trash, splits, chigger bites, (small bends on the rim) and berdan primers. This is also a good time to find .380's

or super's that worked their way into the tumbler. Use a pencile to herd them around on the table. When I pick them up I'll trash

any military cases or others that are swaged. Small circle around the primer. Military cases have a smaller case volume and the swaged cases will usually jam at the primer station.

9mm can be one of the harder cases to load tapered wall and brass from around the world, I don't inspect other cases as close.

45 only to seperate small from large primers and the others at the shaker trays.

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