How much variance in OAL is too much?

Jskd82 · November 20, 2018, 08:57 PM

I've been reloading some 125gr 9mm poly coated bullets and my COAL is very inconsistent. I am trying to 1.125 but have been getting some at 1.135 and some in the 1.110 range. How much variance is allowed before it starts to get dangerous? Also what could be causing this?

I am using a Hornady L&L AP with Hornady dies and I made sure the shell plate is tight.. any other things to check? I am loading Blue Bullets and I notice they have a pretty big variance in weight some 120gr and up to 129 gr, could it just be just these bullets.... is this normal for poly coated bullets? TIA

egd · November 20, 2018, 09:28 PM

If there's that much variance in weight I'd also look at variance in shape and length of the bullet. Unless you have a flat seating stem the stem will usually contact the ogive of the bullet. If the shape of the bullets vary that would mean an inconsistent ogive and that could lead to your big variances.
IMO if you're shooting for 1.125 then 1.120 to 1.130 would be acceptable. others may say less, and of course the less the better.

Jskd82 · November 20, 2018, 10:01 PM

Thanks for the reply... Yeah I'm thinking it's the bullets because I just lowered the seating die a little and ran some thru that came out in the 1.120 range and then I took the loaded ones that were at 1.135 and ran them thru the seating die again and they went in only about .001 to .005. It must be an inconsistent ogive like you mentioned... I have a flat stem for my seating die but I don't wanna take the chance of using it and seating some bullets deeper just to get the consistent OAL.

The 1.130's failed the plunk test but they chamber and eject fine without leaving any marks or pushing the bullet in. What could go wrong if I tried to shoot the ones that failed the plunk test? just mainly feeding issues? thanks.

5whiskey · November 21, 2018, 10:23 AM

That is a fairly large variance, both in OAL and in bullet weight. I usually experience about a .008 or so OAL variance range when I loaded Dardas cast bullets, but most of them were within .005 (and about half within .003) just a few outliers that opened it up to .008. With Missouri cast bullets I'd say my total OAL variance is about .010, but most are still within .005. I'm using a Lee Classic Turret with cheap Lee dies, nothing special.

.025 OAL variance is pretty large, but I would attribute it to the bullets if they have nearly a 10 grain variance in weight. At that bullet weight, that's about 8% variance... pretty big IMO.

egd · November 21, 2018, 10:34 AM

As long as you're not loading anywhere near max I think you would be ok to shoot them. If you are loading in the upper ranges then it might be better to pull those and start over with them.

**Unclenick** · November 21, 2018, 10:42 AM

I think 5whiskey has it about right. For good, consistent bullets, I would expect no more than a few thousandths variation to be normal, and that feeding in a self-loader might push some in another 0.010" or so. Theoretically a 0.025" overly deep bullet would raise the pressure in a maximum load unacceptably, but in reality, primers often unseat pistol bullets before the powder burns much, so you don't normally hear of guns being damaged by this. (Of course, once a gun is damaged and the bullet gone, it's hard to know if that caused the problem.) Anyway, with those bullets and their extreme variation, I would be sorting them by length and weight and treating the groups as different bullets, or I would stick to light target loads.

Gary Wells · November 21, 2018, 11:07 AM

Might want to consider buying some sample bullet packs from various bullet casters and various bullets and experiment. I've never heard of Blue Bullets. That would be way too much variation in both col and bullet weight.

T. O'Heir · November 21, 2018, 03:18 PM

"...big variance in weight..." That's a huge variance in weight. Might be the coating. Might be the bullet itself. You perchance order one of the 'sample' packs? I'm wondering if that's how they get rid of 'seconds'. Dunno one way or the other though.
"...1.130's failed the plunk test but..." They'll chamber because 1.130" is long way from SAAMI Max OAL for 9mm. 1.169" is the Max. 1.000" is minimum. So none of 'em are dangerous, but they won't be accurate either. They should still 'plunk' though.

hdwhit · November 21, 2018, 03:27 PM

I agree with what egd wrote.

Gary Wells · November 21, 2018, 09:46 PM

A honest bullet company is probably not going to give out second class bullets in sample packs. They will probably give out a fair representative of their quality in the sample packs.
A not so honest bullet company will screen out better than their standard quality bullets to screw you on the bigger orders.
A bullet company going under would probably screw everybody on both sampple packs and big orders.
At least that's the way that I see it and even though that's my personal opinion and my past experience with companies in general.

November 20, 2018, 08:57 PM	#1
Jskd82 Junior Member Join Date: February 5, 2013 Posts: 11	How much variance in OAL is too much? I've been reloading some 125gr 9mm poly coated bullets and my COAL is very inconsistent. I am trying to 1.125 but have been getting some at 1.135 and some in the 1.110 range. How much variance is allowed before it starts to get dangerous? Also what could be causing this? I am using a Hornady L&L AP with Hornady dies and I made sure the shell plate is tight.. any other things to check? I am loading Blue Bullets and I notice they have a pretty big variance in weight some 120gr and up to 129 gr, could it just be just these bullets.... is this normal for poly coated bullets? TIA Last edited by Jskd82; November 20, 2018 at 09:04 PM.

November 21, 2018, 10:23 AM	#4
5whiskey Senior Member Join Date: October 23, 2005 Location: US Posts: 3,657	That is a fairly large variance, both in OAL and in bullet weight. I usually experience about a .008 or so OAL variance range when I loaded Dardas cast bullets, but most of them were within .005 (and about half within .003) just a few outliers that opened it up to .008. With Missouri cast bullets I'd say my total OAL variance is about .010, but most are still within .005. I'm using a Lee Classic Turret with cheap Lee dies, nothing special. .025 OAL variance is pretty large, but I would attribute it to the bullets if they have nearly a 10 grain variance in weight. At that bullet weight, that's about 8% variance... pretty big IMO. __________________ Support the NRA-ILA Auction, ends 03/09/2018 https://thefiringline.com/forums/sho...d.php?t=593946

November 21, 2018, 10:42 AM	#6
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	I think 5whiskey has it about right. For good, consistent bullets, I would expect no more than a few thousandths variation to be normal, and that feeding in a self-loader might push some in another 0.010" or so. Theoretically a 0.025" overly deep bullet would raise the pressure in a maximum load unacceptably, but in reality, primers often unseat pistol bullets before the powder burns much, so you don't normally hear of guns being damaged by this. (Of course, once a gun is damaged and the bullet gone, it's hard to know if that caused the problem.) Anyway, with those bullets and their extreme variation, I would be sorting them by length and weight and treating the groups as different bullets, or I would stick to light target loads. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

November 21, 2018, 03:18 PM	#8
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	"...big variance in weight..." That's a huge variance in weight. Might be the coating. Might be the bullet itself. You perchance order one of the 'sample' packs? I'm wondering if that's how they get rid of 'seconds'. Dunno one way or the other though. "...1.130's failed the plunk test but..." They'll chamber because 1.130" is long way from SAAMI Max OAL for 9mm. 1.169" is the Max. 1.000" is minimum. So none of 'em are dangerous, but they won't be accurate either. They should still 'plunk' though. __________________ Spelling and grammar count!

November 20, 2018, 09:28 PM	#2
egd Member Join Date: April 15, 2016 Posts: 73	If there's that much variance in weight I'd also look at variance in shape and length of the bullet. Unless you have a flat seating stem the stem will usually contact the ogive of the bullet. If the shape of the bullets vary that would mean an inconsistent ogive and that could lead to your big variances. IMO if you're shooting for 1.125 then 1.120 to 1.130 would be acceptable. others may say less, and of course the less the better.

November 20, 2018, 10:01 PM	#3
Jskd82 Junior Member Join Date: February 5, 2013 Posts: 11	Thanks for the reply... Yeah I'm thinking it's the bullets because I just lowered the seating die a little and ran some thru that came out in the 1.120 range and then I took the loaded ones that were at 1.135 and ran them thru the seating die again and they went in only about .001 to .005. It must be an inconsistent ogive like you mentioned... I have a flat stem for my seating die but I don't wanna take the chance of using it and seating some bullets deeper just to get the consistent OAL. The 1.130's failed the plunk test but they chamber and eject fine without leaving any marks or pushing the bullet in. What could go wrong if I tried to shoot the ones that failed the plunk test? just mainly feeding issues? thanks.

November 21, 2018, 10:34 AM	#5
egd Member Join Date: April 15, 2016 Posts: 73	As long as you're not loading anywhere near max I think you would be ok to shoot them. If you are loading in the upper ranges then it might be better to pull those and start over with them.

November 21, 2018, 11:07 AM	#7
Gary Wells Senior Member Join Date: August 22, 2009 Posts: 180	Might want to consider buying some sample bullet packs from various bullet casters and various bullets and experiment. I've never heard of Blue Bullets. That would be way too much variation in both col and bullet weight.

November 21, 2018, 03:27 PM	#9
hdwhit Senior Member Join Date: June 22, 2017 Posts: 1,011	I agree with what egd wrote.

November 21, 2018, 09:46 PM	#10
Gary Wells Senior Member Join Date: August 22, 2009 Posts: 180	A honest bullet company is probably not going to give out second class bullets in sample packs. They will probably give out a fair representative of their quality in the sample packs. A not so honest bullet company will screen out better than their standard quality bullets to screw you on the bigger orders. A bullet company going under would probably screw everybody on both sampple packs and big orders. At least that's the way that I see it and even though that's my personal opinion and my past experience with companies in general.