How Deep is Too Deep?

[vortex0178 3]

No, it's not a dirty joke

 

I was reloading some more 9mm on the LNL AP and the OALs started to open up on me again - my target is about 1.069, and got a few that were in the 1.052-1.062 range. Are these shorter rounds okay to shoot, or should I lengthen them a bit with the kinetic puller? I read somewhere that after 1/16th" - 1/8th" you start running into potential pressure issues with 9mm - is that true? My difference is about 1/64th" - should I be worried?

 

Not positive why the OALs fluctuated more this time, but it's either because I had some deprimed/resized/expanded brass already in the mix with my recently-tumbled-just-fired brass, or because I added a split lock ring between the shellplate washer and bolt. I'll do a few more controlled tests to figure out why.

[Old School 611]

No, it's not a dirty joke

 

I was reloading some more 9mm on the LNL AP and the OALs started to open up on me again - my target is about 1.069, and got a few that were in the 1.052-1.062 range. Are these shorter rounds okay to shoot, or should I lengthen them a bit with the kinetic puller? I read somewhere that after 1/16th" - 1/8th" you start running into potential pressure issues with 9mm - is that true? My difference is about 1/64th" - should I be worried?

 

Not positive why the OALs fluctuated more this time, but it's either because I had some deprimed/resized/expanded brass already in the mix with my recently-tumbled-just-fired brass, or because I added a split lock ring between the shellplate washer and bolt. I'll do a few more controlled tests to figure out why.

 

Red- This I don't understand...??

 

As far as length - The consistancy of the nose of the bullet varries at times and will effect your COL. Be concerned about how much bullet is in the case where the powder/ air are. this is what matters.

 

If you have .015" variance in COL I think you could be closer but unless you are near max load I'd shoot them.

 

Look for two things. Crud building up in your seating die and flex somewhere in your press. Both could cause a variation in COL.

 

Of course I accept no liability for any kind of advise.

[tony357 386]

What bullets are they?

[Old School 611]

What bullets are they?

 

Tony- Do you pretty much agree with me?

[tony357 386]

Tony- Do you pretty much agree with me?

 

Yes.. I am curious what bullet he is using..

 

have had diffrences with bullet brands.. The DP 9mm's i just purchased give me a wide range..

 

I just set them up to stay in specified range..

[vortex0178 3]

@ Old School

 

This time around I had added a split lock washer as I had read that doing so would keep the shell plate bolt tight against the drive hub. Unfortunately, it seems to have been the cause of the OAL fluctuation (probably because I didn't tighten it enough or something) by making the shell plate more vulnerable to press flex (i.e., adding a slight spring that could potentially allow more tilt). I removed the lock washer and my OALs became more or less consistent again.

 

I had also mixed in some processed (resized/expanded) brass in with my just tumbled brass, which created a difference in force applied at the top stroke, depending on which type of brass was entering the sizing/decapping die. I isolated out the few pieces of processed brass and ran those separately, and I found that they tended to seat shorter than the unprocessed brass by about .003-.005", again most likely due to less press flex at the top stroke.

 

@ Tony

 

I'm loading Berry's DS-HBFP 124gr, at light target loads (3.7gr Titegroup). With my pistol and this bullet type, 3.3gr Titegroup resulted in a consistently weak ejection (right next to my hand) so I should be in the mid/low load range for this bullet/powder combo.

[tony357 386]

berry's are good they usualy stay close to each other..

[Babaganoosh 192]

3.7 with a 124gr bullet is really really light. To make the minimum power factor for uspsa I run 4.1 of tg with a 124 gr berrys bullet. Tg will tend to run a little dirty with light loads like that. I'd bump it up a little.

 

As for the plate coming loose I use a small dab of loctite. The non permanent type.

 

[Dan 177]

Being a new LnL loader myself. I also experience some variation of around .01 with my COL's. I'm running a medium-light load of 5.2gr HS-6 pushing 124gr FMJ's. I did notice that these bullets tend to vary a bit with the shape of the nose. I take it that is causing the OAL variation. They are bulk purchased Armscor brand bullets. Since then I've shot about 100 of these, with no problems. .01 is very small, although it does look very noticable on the digital micrometer.

 

I have an order of 124gr Extreme plated bullets on the way, and I am curious on how consistent they will be regarding OAL's.

[raz-0 1,259]

If you are running mixed head stamp range pick up brass, you are going to see oal variation. 0.003 and under, and I wouldn't even check the press setup.

 

[Edited to fix brain far typo of 0.030]

Edited February 20, 2012 by raz-0

[Old School 611]

If you are running mixed head stamp range pick up brass, you are going to see oal variation. 0.03 and under, and I wouldn't even check the press setup.

 

Why do you think the brass would effect the COL? Explain...

[raz-0 1,259]

Why do you think the brass would effect the COL? Explain...

 

Empirical evidence. I've tried to dial it out of multiple presses, and you cannot without resorting to performing QC on the components going in. Mixing head stamps and lots on brass introduce component variation, not every brand has the same wall thickness, nor same dimensions on the extractor groove. Lot to lot, wear on the manufacturing equipment can affect those dimensions as well. On top of that, cheap bulk components are only so consistent, so you have variation in them as well. Make it range pick up that may have been reloaded before, as well as being shot out of a variety of guns, and due to how much the brass has been worked due to multiple loadings, or looser/tighter chambers, you'll have wall thicknesses that vary as well as extractor rims that may have been distorted, and general stretching that may show up in any critical dimension. As to why this has a negative effect on consistency of OAL.

 

1) You ever notice how every single shell holder ever has a groove in it which is used to retain the cartridge at the very least on the up stroke when the case is pulling out of the dies? Well, most of them don't necessarily allow every piece of brass to actually lay flush with the bottom of the shell holder or the sub plate on a progressive shell plate. This is due to variations in how the extractor groove is dimensioned. Even if they did sit flush on the down stroke, it wouldn't matter on the up stroke, and with things like taper crimps and whatnot, you actually change the OAL with that part of the process. It causes less deviation on a single stage because the single case shell holder is concentric with the case and fairly rigid, however on a progressive, I have yet to see a press design that doesn't permit some plate flex. If you have a gap, the resizing station will usually cause some flex as it is usually the station with the most force exerted on it earliest in the downstroke. This causes the spacing between the seating dies and the shell plate to change. Usually with that side of the shell plate lifting slightly. It'll change your OAL simply because at the very least the plunger that the bullet pushes against in the die will be touching a slightly different part of the ogive.

 

2) Especially with a lee FCD in the crimp station, but with any taper crimp in general, you will find OAL grows a bit with most pistol cartridges after being crimped. Case wall thickness, and overall cartridge length can affect this. The former does so by how much the cartridge binds in the die. The more binding, the more force exerted when you pull the cartridge out. the less binding, the less force. This affects finished OAL. Case wall thickness varies between brands, lots, and is affected by number of times sized, fired, and reloaded as well as being fired in loose chambers.

 

3) variation in bullet consistency. Take a seating die apart. You will see they contact the ogive rather than the tip of the bullet. They contact the bullet where the bullet's ogive describes a certain diameter. Bullets are imperfect and thus you will find that where that given diameter falls on a given bullet varies slightly from it's neighbor, and thus where a given seating dies set at a specific position will contact them will be different. This changes OAL. In my experience, truncated cone profiles exaggerate this the most.

 

I've fond that if I sort by headstamp using brass that is from the same lot and fired and reloaded the same number of times, I can get very consistent OAL on a single stage press. Mathematically WAY less than 0.01 variance average, but practically speaking although I had less rounds over or under my target length, the maximal variance was about the same as with a progressive press, which was a range of about 0.015 in variation For reference, I'll say I only experimented with stuff I bought new and was known once fired n the first loading, after that it just got dumped in the big pile of brass to reload.

 

Also, especially with progressive presses, as you use them a lot, they get sloppier.

 

I've also experimented with sorting finished loads by OAL and chronoing them. Their velocity spreads overlapped between OAL groups significantly. Given that velocities were consistent within the < 0.004 slop I was getting with zero QC on the brass other than looking for splits and damaged case rims, it's reasonable to say that the pressure curves were similar between them and there was no safety issue. I also noticed no functional increase/decrease in accuracy between groups. However, I'm not the most accurate pistol shooter. I'm only good for about 4.5" at 30 yards if I'm trying, and I'm better than I was back when I did this.

 

These days, I seat with a micrometer seating die, and if I'm seeing more than 0.030 variance with high frequency of variance, I'll diagnose press setup. If I'm below 0.030, and I'm not pushing the max book loads, I'll leave it be. If I am pushing max book loads, I'll hand pick a range of headstamps and beat up and nice loking brass, load them, measure the variance, and use the micrometer adjustment to easily bring sizing in line to keep max length in a functional zone for my guns, and stay above minimum OAL for the charge. I have yet to run into a situation where I could not accommodate both conditions.

 

 

[Edited to fix brain fart typoes]

[Old School 611]

raz-0 - I read you post. I agree with some disagree with some. I'm watching the thread and please do the same. Tomorrow I'll pull out the note book and measure some off the shelf reloads with mixed cases and post the COL of 10 random reloads and velocities and std deviations that were previously recorded..

 

Very interesting topic.

 

BTW hung out with a few benchresters a little yesterday....Now those guys are nuts...LOL

[Old School 611]

raz-0- attached is the load data I assembled and I hold no liability that this is safe for anybody else. I think it discounts some of your statements and findings. These loads have been assembled on a Dillon 550B with Dillon carbide dies.

Loading Data 9mm 115gr FMJ.pdf

[Old School 611]

Just bumping this because peeps seamed to be interested. Check out my pdf as this is real data with out speculation.

[zoid 24]

I get fluctuations like that as well. Can't really pin it down, but the info as some have posted makes sense.

I did not get any issues in function or could tell a difference in pressure. So I just let it be.

[raz-0 1,259]

raz-0- attached is the load data I assembled and I hold no liability that this is safe for anybody else. I think it discounts some of your statements and findings. These loads have been assembled on a Dillon 550B with Dillon carbide dies.

 

We are not actually in much disagreement. I just typed 0.030 instead of 0.003 and kept typing the same thing. I hate it when I do that, sucks to look like a dumbass because you weren't proof reading properly. Yes going from 1.135 to 1.105 would be severe variation. I wouldn't worry about 1.000 vs 1.010 unless you are really pushing the envelope, and I wouldn't try chasing down the discrepancy of 0.003" by fiddling more with the machine. Editing my posts to reflect that. Been doing way too much of the touch typing substitution type typos lately. My brain thought 30 thousandths for some reason at the start, and my hands kept typing 030 and 040. Probably would have been better off giving examples of the actual numbers.

 

I'm still not seeing as consistent OALs as you are in random mixed brass though, although I am seeing less than 0.010 spread on random brass with reasonable press setup and care. Usually I'm seeing variations like 1.130-1.137 on my .40 with random range brass and a casual setup. If I sample, set up for the middle of variation or at one end of variation doing it one cartridge at a time, then fine tune on random 4 round selections a few times over the first 100 rounds, I can usually get it/keep it to ~0.004 for variation and either limit it at the high end, low end, or aim for the middle of the variation, which I found to be a PITA until I got a micrometer seating die. .40 due to bullet profile and the fact some vendors have pretty "tall" brass and others pretty "short" brass, if I want to go below that, I at the very least have to cull certain headstamps. 9mm and .45 aren't so bad, and I can usually keep it to 0.003 with them and a little effort put into setup.

 

moving away form the lee FCD in .40 and to a dillion taper crimp has helped with measured OAL, but I think half of it is because it helped with concentricity. The other half is because without the sizing ring, it doesn't pull on the bullet nearly as much when the cartridge is pulled out.