how much should OAL vary in reloads ?

[wally1229]

I am getting varriations in my over all length from 1.125 - 1.129. I am loading . 40 180gr lead fp using a dillon 650 press.

what is the tollerance for the oal? and is there something I should check or look for on my press?

Thank's Wally

[G-ManBart]

That's a pretty reasonable variation and especially so with lead. Lead bullets are rarely exactly identical (moreso than jacketed) and depending on whether the seating stem contacts the nose of the bullet or somewhere on the ogive will change things as well.

Further, the first three or four rounds loaded will usually be different than all of the rounds after that. For some reason or another, not having all the stations with a case makes a difference. The last couple of rounds will often be a bit different as well, for the same reason. I always forget which way it works, but I think the early rounds loaded with empty stations in the press are normally shorter by a couple of thousandths and the last couple are longer by a few thousandths.

In other words, I set my .38SC OAL at 1.235" and the first couple will often be closer to 1.230" and the last couple closer to 1.240". I'd say the typical range I see is 1.232 to 1.238". It's not enough to make a noticable difference in chrono results and my guns runs fine at either length. For .40 I like 1.200" and I'll get a range from around 1.195 to 1.205...give or take.

Keep in mind mixed brass can also cause some variation as well. All those things added up, you're doing fine with what you're seeing. R,

[wally1229]

That's a pretty reasonable variation and especially so with lead. Lead bullets are rarely exactly identical (moreso than jacketed) and depending on whether the seating stem contacts the nose of the bullet or somewhere on the ogive will change things as well.

Further, the first three or four rounds loaded will usually be different than all of the rounds after that. For some reason or another, not having all the stations with a case makes a difference. The last couple of rounds will often be a bit different as well, for the same reason. I always forget which way it works, but I think the early rounds loaded with empty stations in the press are normally shorter by a couple of thousandths and the last couple are longer by a few thousandths.

In other words, I set my .38SC OAL at 1.235" and the first couple will often be closer to 1.230" and the last couple closer to 1.240". I'd say the typical range I see is 1.232 to 1.238". It's not enough to make a noticable difference in chrono results and my guns runs fine at either length. For .40 I like 1.200" and I'll get a range from around 1.195 to 1.205...give or take.

Keep in mind mixed brass can also cause some variation as well. All those things added up, you're doing fine with what you're seeing. R,

That makes sense because I started out setting my bullet seat depth with a empty press , I just kept using a dummy case until i get the oal right, I had it set @ 1.126 and when I started up and got rolling I checked again and it was @ 1.130 or something way out there so I adjusted down as i went with the turret full.

Thank's for the heads up.

By the way I'm loadind .40 with a 180 lead fp over 4.7 WST has any one ever used this load?

Thank's Wally

[wide45]

By the way I'm loadind .40 with a 180 lead fp over 4.7 WST has any one ever used this load?

Thank's Wally

I think you are over published loads at the length you say you are using. Don't know if it would be safe in your gun. I load longer OAL.

Edited August 12, 2009 by wide45

[texasdog]

By the way I'm loadind .40 with a 180 lead fp over 4.7 WST has any one ever used this load?

Thank's Wally

I think you are over published loads at the length you say you are using. Don't know if it would be safe in your gun. I load longer OAL.

My OAL is 1.2 with my 45ACP rnf. If I make it much longer it will get stuck in my Wife's Glock 21. My 1911 can handle a longer OAL though.

[wide45]

My OAL is 1.2 with my 45ACP rnf. If I make it much longer it will get stuck in my Wife's Glock 21. My 1911 can handle a longer OAL though.

Texasdog, we are discussing .40, not .45

Edited August 15, 2009 by wide45

[Sarge]

Yes the oal's do vary. As stated the first few are short. But if you take the time to pull some out of the bin when finished you will notice the same headstamps measure the same oal pretty regularly. So as stated different brass will affect it and it is common to be a tad off.

[MemphisMechanic]

I set my .38SC OAL at 1.235" and the first couple will often be closer to 1.230" and the last couple closer to 1.240". I'd say the typical range I see is 1.232 to 1.238".

Same here. I load 9mm for Production, using both 147 Precision Delta RN FMJ, and a Black Bullets flat-nose 147 moly.

My 'target' OAL is 1.030" ... and I see everything from 1.125" to 1.140"

Runs great.

[GrumpyOne]

I set my .38SC OAL at 1.235" and the first couple will often be closer to 1.230" and the last couple closer to 1.240". I'd say the typical range I see is 1.232 to 1.238".

Same here. I load 9mm for Production, using both 147 Precision Delta RN FMJ, and a Black Bullets flat-nose 147 moly.

My 'target' OAL is 1.030" ... and I see everything from 1.125" to 1.140"

Runs great.

You mean 1.130, right?

[Front Man]

If you can keep it + or - .005 youare doing fantastic!

Human hair = .002?

FM

[steel1212]

I just skimmed this but if your using mixed brass your OAL will vary also. It will also vary if your brass is mixed times fired, I.E once fired vs 3-4 times fired. When I use 1 head stamp once fired brass my OAL tends to be around +- .001 In my .40 loads I set it up to try to hit 1.180 and I might be 1.179-1.181 but mostly it will be dead on. Mixed brass I'll get probably +- .005 or so.

[Pat Miles]

Keep in mind that lead bullets get dinged up during manufacturing, boxing, shipping and then when you pour them in a bin (if you do) on your loader. Doesn't take much to show a .003"-.005"difference in OAL.

CYa,

Pat

[CocoBolo]

Variation will happen with the stations full or not full. I also found that the seating die can cause this. With the 40 185gr precison I use a flat seater rather than the cupped seater insert. In a Hornady Seating Die you can change the seater insert depending on the bullet shape for more consistent results.

I don't think that a variation of even .010 will have much effect, unless its too long and the gun fails to go into battery, now thats a problem.

[Pezco]

Wally,

Corey is right on the money with the effects of the brass. I also us an XL650 for my Limited guns and discovered the impact of the brass after about 2,000 rounds loaded.

Currently (25K loaded) I clean, separate brass by head stamp then load and can get the OAL variation down to about + or - .0015 so you are doing well unless that is new brass. New Starline brass I'll get around + or - .001.

My data is currently in my load book and at some point I'll put it in Excel because I'm and Engineer and thats what we do. I'll publish the results when that happens.

Hope this helps.

[Bongo Boy]

I have no idea how much they 'should' vary, or even how important it is to narrow up the range of variation. But I like statistics a lot, so I ran some for my loads using a Lee Classic Turret.

Conditions: mixed brass, Wolf primers, cast bullets. Two different 'lots' if you will, having run 50 of these rounds with one charge, and the second 50 rds using a different charge.

Average OAL is 1.155" with a standard deviation of 0.005". So, if your maximum variation is .004", that's significantly more consistent than my loads, since my stats mean that 2/3 of my loads (approx) will be within .005, the remainder will be even further away than that. These are .45 ACP, but I see no reason to think variation is sensitive to small differences in average case length. The entire process should be equally consistent for any round within a small range of average lengths and within some small range of average calibers. What I'm saying is, the OAL variation you see with a .40 SW I'd expect to also see in 9mm or .45 ACP, approximately and all other things being similar.

I also ran a process quality check...it's based only on the actual data and assumes all 100 rds came from exactly the same 'process', which for all practical purposes I think is reasonably fair to say. That analysis says that I should fully expect, within the limits of my process, to have OAL vary by .010" plus or minus. To put it another way, given all the variables that are 'normal' for my handloading process (me, the machine, the components, etc), I shouldn't look for an 'error' in the process unless my loads are longer than 1.065" or shorter than 1.045".

This of course has NOTHING to do with how much they 'should' vary based on any user criteria...it merely says this is how much they should vary if I consistently handload using the same technique, equipment, component and environmental variances.

Based on what I feel are reasonably consistent operator behaviors (i.e., me), I have to say you have a consistent process. If you'd like to give me 50 or a hundred actual measurements given in the order the widjets come out of the press, I'd be glad to run a few charts you could hang on you wall.

Edited August 16, 2009 by Bongo Boy