OAL acceptable variation

[Magnus]

Hello, mostly new reloaded with only about 500 9mm round nose so far. (Dang primer shortage hit right as I tooled up)

 

Loaded on an RCBS turret with Lee steal dies.

 

I stumbled across a couple hundred primers and broke the gear back out, and wanted to try my hand at hollow points. First thing I did was start practicing setting up the bullet seating die and making a couple dummy rounds. I set my die up with my first round, verified with the second. Then cranked out 3 more.

 

When I measured the OAL there seemed to be a large variance in the rounds. I pulled the bullets and repeated. I got the same results. Pulled the bullets again and repeated, but this time measuring after each press. Variation present again. I pulled the seating stem out and put it on top of the bullet and drew a line around the ogive. Measured that line to the bottom of the round and found what some of you already likely know. There was my variation.

 

How do you control for this variance? I can baby each round while in a single stage turret, but what happens when I put my dies in my Dillon and crank out 100+ rounds?

 

Thank you,

Jason

 

 

[Rnlinebacker]

Get a Redding competition seating die. Extremely precise

[Boomstick303]

What was the variance?  

 

 

[Johnny_Chimpo]

30 minutes ago, Magnus said:

Hello, mostly new reloaded with only about 500 9mm round nose so far. (Dang primer shortage hit right as I tooled up)

 

Loaded on an RCBS turret with Lee steal dies.

 

I stumbled across a couple hundred primers and broke the gear back out, and wanted to try my hand at hollow points. First thing I did was start practicing setting up the bullet seating die and making a couple dummy rounds. I set my die up with my first round, verified with the second. Then cranked out 3 more.

 

When I measured the OAL there seemed to be a large variance in the rounds. I pulled the bullets and repeated. I got the same results. Pulled the bullets again and repeated, but this time measuring after each press. Variation present again. I pulled the seating stem out and put it on top of the bullet and drew a line around the ogive. Measured that line to the bottom of the round and found what some of you already likely know. There was my variation.

 

How do you control for this variance? I can baby each round while in a single stage turret, but what happens when I put my dies in my Dillon and crank out 100+ rounds?

 

Thank you,

Jason

 

 

 

Many bullet styles don't have a lot of control over the length from the base to the tip due to the particular way in which they're made.

 

A better way to measure bullet length is from the base to the ogive.  The ogive, in case you don't know what it is, is the transition point from the nose profile to the full diameter of the bullet.

 

Any number of companies make tools to measure that.  I use a Sinclair comparator which is used in conjunction with a pair of calipers.

 

But more to the point, we're talking handguns here not precision rifles.  That level of compulsion about certain details is unnecessary.  Once I set my seating die to an OAL that will let loaded rounds pass a plunk test, I never check it again.

[Dirty_J]

I don’t look twice at a variance of +/- 0.005”

 

This ain’t PRS. 

[Magnus]

24 minutes ago, Boomstick303 said:

What was the variance?  

 

 

1.169 - 1.148 target was 1.169

2 were within .005 and I did not care. But I had 1 at 1.148 and 1 at 1.149

Seemed excessive to me.

[CC3D]

Several people have already said it here, but just to give you even more confidence, +/- .005 is my acceptable variance. If they're on the high side I plunk test them to be safe. 

[Magnus]

2 minutes ago, CC3D said:

Several people have already said it here, but just to give you even more confidence, +/- .005 is my acceptable variance. If they're on the high side I plunk test them to be safe. 

Agreed. 2 were on the .02 short side. That's what made me hit the breaks.

[CC3D]

Yep, that is wayyyy too much. Keep us posted on what you find out, I have trouble believing that much variance is coming from the die itself.

[Johnny_Chimpo]

1 hour ago, Magnus said:

1.169 - 1.148 target was 1.169

2 were within .005 and I did not care. But I had 1 at 1.148 and 1 at 1.149

Seemed excessive to me.

 

Is that base to tip or base to ogive?

 

One matters a whole lot more than the other.

[Magnus]

11 minutes ago, Johnny_Chimpo said:

 

Is that base to tip or base to ogive?

 

One matters a whole lot more than the other.

Base to tip.

[Johnny_Chimpo]

Just now, Magnus said:

Base to tip.

 

As long as they slide up the magazine, it doesn't matter.

 

Whose bullets are you using, out of curiosity?

[Magnus]

I pulled the bullets, set the seater stem on the bullet, and drew a line around where the die comes down to. You can see the line is not consistent. Looking much closer, some bullets bottom out in the seater die, and some rest on the rim of the 'cup'. I took pics, but the images are to large to upload. 

[Magnus]

4 minutes ago, Johnny_Chimpo said:

 

As long as they slide up the magazine, it doesn't matter.

 

Whose bullets are you using, out of curiosity?

Winchester

[Farmer]

Flat nose seating punch. Ya know someone with a lathe?

[Magnus]

So, Lee replied back to me.

 

"You could order a flat custom bullet seating plug.
https://leeprecision.com/custom-bullet-seating-plug.html
That might help the seating consistency of your bullets."

 

Maybe I'm overthinking, or I'm not explaining my confusion well.

How would a flat plug help. I really don't care about OAL except for to make sure it chambers and is off the lans. The thing that bothers me is that I don't have a consistent seating depth within the shell which will create variable pressure between rounds.

[Steve RA]

If the bullets are not the same length, you will have an inconsistent depth in the case if the overall lengths are the same.  As long as all the cartridges  fit in the magazine and in the chamber I would not worry about the depth of the base of the bullet in the case.

[Farmer]

Your bullets have variable ogives and if your seating plug is shaped to fit a specific ogive that’s where the problem lies. With a flat punch you take those variables out of the equation. Even when seating round nose it’ll still work, you’ll just get a small dimple on the nose. The only problem is that you’ll get variance from the ogive to the lands. If you want them perfect you’ll either have to sort them all with a ogive gauge or get a seating punch that matches your bbl throat.  I have a bunch of “seconds” bullets and that’s what makes them seconds is the nose shape variance. To look at them you can’t see it but when you gauge them there can be up to .040 difference from low to high. 

Edited March 12, 2022 by Farmer

[Brooke]

I agree with everyone who said +/- 0.005 is acceptable. My main reason is that is the best I can do on any Dillon press using properly prepared range brass and I load 50-70 thousand rounds a year, gauge every round and have essentially no failures of any kind in 1911/2011 pistols. My range of acceptance is 1.165 +/- 0.005 for 9 mm and 1.185 +/-0.005 for 0.40 caliber.

 

That said, I disagree with those who are apparently saying it doesn't matter as long as they plunk and spin. It definitely matters in 1911/2011 guns. OAL is the determining factor in feed reliability for 1911 style guns. The reason is the steep (or nonexistent) ramps. It's critical to reliable feeding where the bullet hits the ramp to avoid feeding issues and OAL is the critical measurement. Variability of OAL may be less critical in guns with shallower ramp angles but it is not something to ignore.

 

Posters here have concentrated on oglive shape and geometry variation. For really sorry bullets maybe that's an issue. IDK but a more likely issue with unexplained short rounds is case preparation. First take a cleaned, used casing that has not yet seen a sizing die and drop a bullet into it. Most likely when you do so the bullet will fall deeply into the casing because the case is expanded from being pressurized during prior use. The variability of how far it falls into the case is a result of the guns the case saw. Some have tighter or looser chambers.

 

Run the cases you have observed in the prior paragraph though your sizing die and repeat dropping the bullet into them. You will find that in some cases the bullet still falls too deeply into the case though less so than before sizing. Brass is elastic that's why it works. So sizing a case that was expanded a lot in use will allow it to partially recover from resizing and let the bullet fall in so far the seating die doesn't determine the depth. Thus short rounds.

 

Try this...After sizing but before anything else run your cases though a reliable case gauge like a Shockbottle 100 round gauge. Separate those that will drop into the gauge from those that won't or are tight. Then load several from both piles separately. I bet you find your short rounds come from the pile that won't gauge prior to loading.

 

Also sorting by head stamp will help because some head stamps seem resistant to proper resizing. Bottom line..if the round is too short before it even gets to the seating die you're going to have a round below your desires and one likely to cause you a problem.

[mtwain56]

On 3/9/2022 at 4:49 PM, Magnus said:

Hello, mostly new reloaded with only about 500 9mm round nose so far. (Dang primer shortage hit right as I tooled up)

 

Loaded on an RCBS turret with Lee steal dies.

 

I stumbled across a couple hundred primers and broke the gear back out, and wanted to try my hand at hollow points. First thing I did was start practicing setting up the bullet seating die and making a couple dummy rounds. I set my die up with my first round, verified with the second. Then cranked out 3 more.

 

When I measured the OAL there seemed to be a large variance in the rounds. I pulled the bullets and repeated. I got the same results. Pulled the bullets again and repeated, but this time measuring after each press. Variation present again. I pulled the seating stem out and put it on top of the bullet and drew a line around the ogive. Measured that line to the bottom of the round and found what some of you already likely know. There was my variation.

 

How do you control for this variance? I can baby each round while in a single stage turret, but what happens when I put my dies in my Dillon and crank out 100+ rounds?

 

Thank you,

Jason

 

 

Try using the identical brand & type brass.

[OpenshooterMclass4lyfe]

You’ll have somewhat of a variation due to inconsistency in brass lengths.   So long as your somewhat close it’ll be fine 

[Edd]

sorry if this is in wrong forum: 9mm 124gr berrys hp aol is 1.065  lyman book say 1.075   is the 1.065 to short 4.3 gr bullseye

 

[HesedTech]

On 3/9/2022 at 4:49 PM, Magnus said:

How do you control for this variance?

Here are the issues:

 

1. Quality of bullets.

2. Seating die.

3. Press setup.

 

If you have the same stroke and the distance the press moves, then the first two are your issues. You should not need a custom made seating die unless the bullets are really strange. 

 

I've used Lee dies and they work fine. As others suggest the bullets may be the issue.

[Frankl03]

I switched from a Lee seating die to a Dillion seating dies (Dillion press) . It helped tighten up my variances.

[99mpower]

bullet variation and die setup are critical to consistency.

 

my acceptable tolerance is .005, but I also run my 9mm on the short side for my Tanfo chambers