ARGH!!!!!

[Captain Quack]

I'm sorry to be such a pest everyone but I am having to relearn everything from scratch and all I could find on this subject related to accuracy. I just ran up the first 30 rds of test bullets for my 9mm and when I checked the OAL they ran from 1.112 to 1.144 with a desired length of 1.135. Is this something I have to pull them and start over or is this a acceptable variant? I'm using RMR 9mm FMJ RN with 6.00 gr of Unique and these are for plinking and practice.

Captain Quack.

 

[troy fairweather]

If they chamber shoot them.

 

[mdi]

I'd probably put the really short ones (1.112") in my impact bullet pullet and whack the bullets out to the target OAL. If the longest are too long to pass a plunk test, I'd run them through my seating die and shorten OAL to target length (1.135"). But first I'd find out why I had such a large variation in seating depth...

 

[PO2Hammer]

.032" is a lot of variation for 9mm oal.
I would give my press and dies a complete 'once over', make sure everything is tight.
The oal variation doesn't make the ammo dangerous, the question is is 6 grains of Unique safe at an oal of 1.112" with an RMR (weight???) FMJ?
Don't know.

 

[Captain Quack]

I think some of it may be I'm not pulling the leaver hard enough or too hard. I'll be rechecking my seating die with the ram firmly all the way up. One thing I did notice is that the powder charge went well high up the case close to the top. Unique 6 gr. Could it be that the bullet is seating too deep and compressing the powder? The data I've been using is from Speer 13.

 

[Klaatu Barada Nikto]

Something I started doing years ago with my initial setup was to leave the crimp die long after getting the seating die where I wanted it. Then I would run the crimp die down until I could feel contact, lower the ram and add 1/4 turn more to the crimp die.
After verifying the COL and crimp, gauge block and plunk test I would take the mock up round and press it against my workbench with moderate pressure, then remeasure the overall length. If it didn't move I was good. If it did move I would lower the crimp die another 1/4 turn and repeat the process with another mock up round until the COL quit moving.
Everybody has a routine that works for them.

 

[AJC1]

I can only guess your getting that variable depth for one of two reasons. 1. Your using mixed brass or 2. Your seating and crimping at the same time or both. If I get more than .002 I'm at an all stop and figuring out the cause. My max load for a 115 at 1.090 was 5.8 grains. If you were loading 5 grains no issue but your at max.

 

[Captain Quack]

New routines are always worth exploring. I'm using a Lee factory crimping die.

 

[Klaatu Barada Nikto]

Don't think you mentioned the bullet weight. Is it the RMR 147?

 

[Walkalong]

I think some of it may be I'm not pulling the leaver hard enough or too hard. I'll be rechecking my seating die with the ram firmly all the way up

Seating die down too far?

 

[Captain Quack]

Checked that against my test bullet. Right on 1.135. The idea of just putting the short ones in the bullet puller and giving them wack has been a good one. Thank you. The bullet weight is RMR 115 gr. They had that in stock and I don't mind plinking and practicing with 115. I'm only 35 miles from the shop so it's easy for me to just pop in.

 

[Skinnedknuckles]

It may be that the nose of your bullet does not fit well in the seater plug. If this happens, the nose can tilt slightly and result in different lengths. There are ways to simply modify the seater plug if you have a big mis-match.

 

[Mark_Mark]

have you checked your calipers? make sure they re-zero after opening and closing completely

 

[webrx]

When you seat try to be consistent and fully up. I have myself had a couple vary, went back and made sure I was adjusted for a full seat aka ram fully up and that is where I measure my col. then I check them after crimping. This should tell you if it is seating or crimping changing your col. then run next 5 or 10 and check to make sure they stay there. If the depth is not consistent when seating there is something not right and it will affect your accuracy

 

[Captain Quack]

I re-zero the calipers after every measurement so I'm pretty sure that's not it. The bullet shape offers a possibility. I'm using a factory crimp die. That shouldn't have any affect should it? I ended up pulling about half of them so it's only a few minutes to do them again.

Captain Quack.

 

[Mark_Mark]

obstruction of the press handle?

 

[PO2Hammer]

I'm liking the tilted bullet theory more and more.
It can be a real challenge getting bullets seated straight with the Lee 9mm seating die, especially JHPs.
Roll some of your loaded rounds on a smooth surface and look for bullet wobble.

 

[AJC1]

Another fustrating thing about round nose profiles is that sometimes the tip of the nose gets a flat spot. I use flat nose profiles like the match winner for that reason.

 

[Mark_Mark]

Another fustrating thing about round nose profiles is that sometimes the tip of the nose gets a flat spot. I use flat nose profiles like the match winner for that reason.

that right...

OP, are you using the RN profile bullet seater?

 

[greyling22]

variations in ogive?

 

[bk42261]

I haven't reloaded for years, and even then, not much 9M/M, but that case you show seems like that must be a lot more than 6 Grains?

 

[Ironicaintit]

I haven't reloaded for years, and even then, not much 9M/M, but that case you show seems like that must be a lot more than 6 Grains?

Nah, that looks about right.
I load mine at 5.8 gr of unique and it’s right up there.

captain Quack, if you are seating and crimping in the same step, I’d bet that’s your problem. Especially if you are using mixed case brands.

 

[kalielkslayer]

Are you sure you’re seating die is secure?

I know it’s a stupid question but it happened to me once and I noticed it immediately when I “boxed em.”

 

[NMexJim]

6 grains of Unique is getting pretty hot even for 115 gr. If you’re loading 115 gr then 1.100 OAL is ok although I personally like 1.130 better, and 5.4 grains is at max standard pressure.

If you’re using 124 gr then I think you’re getting a little short and 5.0 powder would be getting close to max for pressure. You did mean 6 grains of Unique, right? That’s a very hot pinker by my books

My notes say I’ve run 6 grains Unique for 115 grain FMJ in the past out of a P35, but I use slide buffers too. You might be clocking 1200+ FPS.

I don’t use Unique anymore and looked this up a couple or three times tonight. Makes me sweat just a bit.

 

[lordpaxman]

New routines are always worth exploring. I'm using a Lee factory crimping die.

My Lee FCD doesn’t seat, it just crimps. I suspect you have the Lee 4 die set with the seater die separate? I wouldn’t expect your FCD to alter your COL. Check your seater die for locked in place and the seating stem tight.
30 bullets aren’t too hard to pull. Here’s where a chrono comes in handy, because you could always load some at 1.130”, 1.125”, 1.120” etc, just shortening COL and seeing how the velocity changes. While velocity can’t tell you the pressure you can see if the changes are linear. Good luck.