9mm exceeding max length

[scott511]

Maybe you guys can help me out here.
I picked up some 147gr FMJ FP to work up a load for suppressor use. I have never loaded 147gr before. I am using Alliant data for Sport Pistol which lists 3.5 grains at 1.08 min OAL. (-10% for starting = 3.1)
I'm getting a pretty good variance in OAL when seating. 1.162-1.175
At this length, even with the variation, every single one plunks in all my 9mm barrels perfectly. I loaded some up at 3.1, and some at 3.3 and test fired with suppressor. The 3.1 would not extract, but 3.3 did; very good grouping and functioned just fine.
Should I be concerned with rounds that are over max length?
I took some that were over 1.169 and cycled through pistol to see if they were getting set back and none were.
The lengths are that long because that's where I started and they all plunked and shot well so I didn't see a need to mess around anymore with seating. Should I try to shorten the OAL some?
Is there a chance of under pressure and possible squib being as they are loaded so long? Or should I just "choot em"?
Thanks,

 

[mcb]

If they feed reliably and fit your magazines I wouldn't worry about it.

 

[ericuda]

What brand of bullets. Looks like you are loaded way long and a bit light. Not around my manuals right now.

 

[swg1]

As long as the rounds aren't so long they are engaging the rifling, you should be good to go. You might have issues if you try your ammo in other guns, but in your gun it sounds like they are working fine. Either color the bullet with a felt marker to see if you are engaging the rifling or spin the round when it is in the chamber, it won't want to spin if it is engaging the rifling.

 

[fxvr5]

Some flat nose bullets loaded to that length won't fit in some magazines. For example, Glock 9mm mags can jam with bullets loaded too long.

 

[scott511]

ericuda- not sure what brand they are; picked them up from a member on another board. They are definitely FMJ FP though and the 20 or so that I weighed were very close to 147 grains.
swg1- every round I loaded plunked into every one of my 9mm barrels. All spin freely while dropped in, and I cycled some through a pistol and none had any setback.
fxvr5- I've tried all these rounds in a variety of mags; several of each M&P, Glock, Magpul. The only place I had an issue was with a 33 round Ammend 2 stick mag. The rounds weren't pushing up. I ran a rag through the mag body and it worked fine after that.
So, I know if seated too deeply they could cause overpressure, but what about really long? Would it go the other way and be underpressure?
I am exactly midway of the data at 3.3, and that data is for a 147gr FMJ FP.
I am inclined to go with what mcb said "if they feed reliably and fit magazine not worry"
The data shows a minimum OAL of 1.08; is it safe to assume that any OAL between 1.08 and 1.169 would be ok?
These rounds will probably only ever be shot by me in my guns.

 

[swg1]

Yer good to go.

 

[Mark_Mark]

STI 9mm and 40 mags... you can load them EXTRA long!!

 

[FROGO207]

If they plunk, load, and eject after firing you are good to go. They might not plunk in another gun so test them if you want to try them in it first.

 

[NMexJim]

To borrow a page from Mr Wobbly.

Flat point usually seat shorter.

 

[swg1]

I'm waiting for someone to get uptight over the pic not showing the headspace correctly.

I get the gist of the pic, my facetious nature is simply showing. Thanks for the pic.

 

[scott511]

If they plunk, load, and eject after firing you are good to go. They might not plunk in another gun so test them if you want to try them in it first.

At this time I can't think of any reason these would be fired in anything other than my guns, and I've tried them in all of mine with no problems.
This post did get me to thinking though; how do manufacturers determine the length to be compatible in most guns? I know there's the whole "xxx ammo won't feed in xxx guns" thing, but for the most part you could buy a box of ammo (when it was available) and it most likely would work in any gun. Do they just pick a length within specs?

 

[film495]

how much of the bullet is in the case? if you have a solid grip - probably not an issue, but you might want to look up on hodgdon's websight - and find a similar bullet and load, and see what they are using for a similar bullet weight and type. speer usualy has some load data to compare too as well.

what seating stem are you using? for 9mm flat point, shouldn't there be a flat end seating stem? OAL should be more consistent than that with a flat bullet and a flat seating stem in the die from my experience.

 

[swg1]

At this time I can't think of any reason these would be fired in anything other than my guns, and I've tried them in all of mine with no problems.
This post did get me to thinking though; how do manufacturers determine the length to be compatible in most guns? I know there's the whole "xxx ammo won't feed in xxx guns" thing, but for the most part you could buy a box of ammo (when it was available) and it most likely would work in any gun. Do they just pick a length within specs?

Industry spec, SAAMI as I recall.

 

[scott511]

how much of the bullet is in the case? if you have a solid grip - probably not an issue, but you might want to look up on hodgdon's websight - and find a similar bullet and load, and see what they are using for a similar bullet weight and type. speer usualy has some load data to compare too as well.

what seating stem are you using? for 9mm flat point, shouldn't there be a flat end seating stem? OAL should be more consistent than that with a flat bullet and a flat seating stem in the die from my experience.

Not sure how much is in the case or even how to measure it. I pushed on them pretty hard on the edge of the bench and they didn't move. I also cycled some through a pistol and re measured and none of the measurements changed.
The data I'm using is for 147 FP.
Looking at the pic that NMexJim posted above, the bullet I have more resembles the one on the right; RNFP.
The seating stem is the one that came with the Lee dies. Pretty sure it doesn't have a flat part on it. I've loaded some 124gr bullets before that had a "flatter" point and don't recall any problems.

 

[bullseye308]

You are good to go. I load some short, some long, just depends on which gun will be shooting them. I load each load specifically for each gun, and I had 6 9mm’s to feed.

 

[kalielkslayer]

You are good to go. I load some short, some long, just depends on which gun will be shooting them. I load each load specifically for each gun, and I had 6 9mm’s to feed.

just the opposite. I’m feeding 6 guns; 3 Glocks, 2 Springfields and a CZ clone. I load for functionality. I load a 100, tell everyone to come to the house and blast 25 each.

If they function in their guns, my Glocks will eat em up.

 

[lordpaxman]

Not sure how much is in the case or even how to measure it.

It involves math. COL - bullet OAL = bullet base seating depth. Case OAL-seating depth=distance bullet is in the case.
Most don’t trim 9mm cases so each case could be a different length.
I load a lot of Sport Pistol and 147’s but usually to 1.120”. You probably wouldn’t make minor PF with your longer length at 3.3gr. If the load works for you and you’re happy, you’re done. If it were me and I knew the 3.1 wouldn’t cycle my gun, I wouldn’t count on 3.3 always cycling it, I’d want a bit more margin on the powder. I wouldn’t expect a squib at either charge weight. Good luck.

 

[scott511]

It involves math. COL - bullet OAL = bullet base seating depth. Case OAL-seating depth=distance bullet is in the case.
Most don’t trim 9mm cases so each case could be a different length.
I load a lot of Sport Pistol and 147’s but usually to 1.120”. You probably wouldn’t make minor PF with your longer length at 3.3gr. If the load works for you and you’re happy, you’re done. If it were me and I knew the 3.1 wouldn’t cycle my gun, I wouldn’t count on 3.3 always cycling it, I’d want a bit more margin on the powder. I wouldn’t expect a squib at either charge weight. Good luck.

Good to know
So, if you wouldn't count on 3.3 always cycling the gun, would you:
A. Leave at 3.3 but seat deeper
or
B. Bump up the charge
The max is 3.5

 

[film495]

when I was messing with RN 9mm, my OAL seemed to drift a little round to round. when i looked into it - that is normal from variances in the bullets, but it should not be much. if you have a flat seater stem, it in theory should come out exact round to round. I have some RNFP to experiment with, but haven't yet.

 

[rfwobbly]

I'm waiting for someone to get uptight over the pic not showing the headspace correctly.

I'm reminded of a quote from Albert Einstein, who said... "In my contempt for authority, I became the authority."

Well then my friend, you are welcome to become the new artist in residence. But I warn you, knowing the way is not enough. You'll also need to drive the car.

Ready. Set. Go !

BTW... That graphic was first presented in Dec 2009.

 

[lordpaxman]

I would chrono, or find someone who has a chrono. That would really help know where you are wrt published data. Then when you change either COL or charge weight, you can see how that translates to velocity changes.
There’s no right or good answer to A or B. Your gun(s) may like either, neither or both. If you don’t care about a possible cycling problem and the loads are performing to your expectation you don’t have to do anything. There’s only a .2gr difference between your two loads and if you’re using a progressive or powder measure you could easily hit one or the other. That’s the only reason I would have a bit more wiggle room. Shortening the COL will give you a bit more neck tension and yes a bit more velocity. I’d do that first, maybe .010” and then .020 just to see. While the Alliant load data has 3.5 max, remember that’s at 1.080” but for their components and test setup.

 

[rfwobbly]

Some things to consider...
• The inside of the chamber is highly machined to a very tight tolerance and very fine finish. The inside of the mag is not. It is made of folded sheet metal, which is usually spot welded at over-laying layers of the sheet. The welding (what ever kind is used) produces local areas of distortion. So the inside of the mag is quite rough, and bullets (like JHP) with sharp edges, or corners on the ogive or meplat can get easily snagged and hung up.

• Second thing to remember is that the mag is not straight up/down, it's canted back at 10° to 15° to fit the grip angle. Therefore, due to the geometry, the effective space inside the mag is lessened for fitting horizontal cartridges.

► For those reasons I would suggest a nominal OAL be no longer than 1.160". And even much less for JHP with sharp edges.

 

[scott511]

Good points rfwobbly

 

[swg1]

You find malice where none exists. I have no issues with your graphics. My sarcasm was directed at the potential poster that finds the most inconsequential detail and then proceeds to wail endlessly at the affront.

I hope that clears the air, you have my apologies over any perceived offense. None was intended.

I'm reminded of a quote from Albert Einstein, who said... "In my contempt for authority, I became the authority."

Well then my friend, you are welcome to become the new artist in residence. But I warn you, knowing the way is not enough. You'll also need to drive the car.

Ready. Set. Go !

BTW... That graphic was first presented in Dec 2009.