I recently posted a range report on another forum about shooting 3 different 9mm handguns with reloaded ammunition. In that post, I noted that my reloads were too long for the S&W M&P9 2.0 compact. The first round I tried fired, but the second failed to go fully into battery and jammed the gun. These very same loads functioned fine in my HK VP9, Sig P365, Ruger SR1911 Cmd and Ruger SR9C. I was using Winchester brass and Sierra 125 gr JHP's. The data that I used was from LoadData.com. It listed 1.130" as the COAL of their loads tested with that bullet. I later downloaded Sierra's Volume 6 reloading data app to my iPhone. Their data shows an overall length of 1.030", or .1" shorter than LoadData.com's data. At first I thought I might have misread LoadData's info. I did some digging and found a printout I made and sure enough it said 1.130".

Tonight I read an article in the January 2021 issue of Shooting Times. The article was entitled "Fast 9mm Loads." I was surprised to find that they too discovered the the M&P's have a short-throated chamber. As a result, they had problems with their handload's COAL functioning in their M&P. They ended up shooting them in a Glock 19.

I have loaded thousands of rounds of ammo for semi-auto pistols over the years. The majority of these were .45 Auto, but many were .40 S&W and some were .380 Auto and .38 Super. I have had more difficulty reloading the 9mm rounds, than all the others combined. I find that they are pickier about case length, and now I find that there are some differences in chamber throats too. They say that there are more 9mm handguns in the world than any other. You would think they would be more uniform.

As a side note, shortening overall length as much as .1" can cause a rise in chamber pressure. I need to revisit my powder charges to make sure they are safe. I refuse to maintain different COAL's for different guns. I will drop all my 9mm handloads with 125 gr Sierra's overall length to 1.030" They should still function in my VP9, P365, SR1911 and SR9C. Have any of you have noticed this problem in your M&P's?

Don't feel bad.

Many years ago I loaded that same Sierra bullet in my old Radom 9mm pistol and also had feeding problems.

Some bullet shapes just have problems in some weapons if the OAL or FPS is not just right.

Right now the new S&W is getting broken in with factory "Ball" ammo, with the stiff new recoil spring and sharp edges.......
Too early for light loads, yet.

Good luck getting it right for that pistol.

" The data that I used was from LoadData.com. It listed 1.130" as the COAL of their loads tested with that bullet. I later downloaded Sierra's Volume 6 reloading data app to my iPhone. Their data shows an overall length of 1.030", or .1" shorter than LoadData.com's data."

Your problem is the error in the LoadData. The American standard for Minimum chamber size and maximum ammunition is contained in SAAMI drawings. SAAMI
With the Sierra bullet that is fatter up front than the usual secant ogive shape, Sierra correctly shows it loaded shorter to obviate the bullet ogive impinging on the rifling in a SAAMI minimum chamber.
There is no standard for the MAXIMUM Freebore a pistol chamber may have, and in fact they vary widely. Had your first pistol been an STI competition 9mm and you loaded to its maximum, the resulting ammunition would not have functioned in any of the guns you listed. In other words, the STI will accommodate extra long bullets not normally loaded in 9mm.

What you need is a 9mm cartridge gauge, which will assure your reloads will fit any SAAMI spec chamber, not just the gun you happen to have now. About $25, available from many sources.
L.E. Wilson Max Cartridge Ga 9mm Luger

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...in my 9mms. I had more trouble getting those to chamber in all of my guns. I used a 1000 of them and I'm not buying more.

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The 9mm Luger with cast bullets / reloaded ammo is a Nasty Little Stinker !
The smaller the gun , compact and subcompact , the worse it is . I've found most new 9mm's , especially the small ones , have little or no throat ! Where the chamber ends the rifling starts ... and this is where the ammo chambering problem lies . In these guns the bullets must be deep seated to pass the "plunk" test .
Other than a "throat job" on these pistols there isn't much else you can do . I find Truncated Cone bullets easier to get to "plunk" than Round Nose ...sometimes the ogive on RN's hits the lands before fully chambering and these have to be seated rather deeply ... The TC's are easiest to get to chamber ...but still must be seated deep enough to pass the "plunk" test.
Gary

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I have a Wilson gauge for 9mm and those rounds dropped in nicely and do not extend above the top of the gauge. However, if I remove the barrel and drop in a round, it does not fully seat. Those Sierra bullets have a different ogive than other 9mm bullets I shoot. That seems to be the main cause of the problem. My M&P just doesn't like them unless they are seated well below SAAMI COAL specs.

Yeah I bought a thousand a while back also. The are really accurate in my 9mm's, but are really picky on overall length. If I can ever find Hornady 124 gr XTP's again, I'll stock up on them. They have never given me any issues when I do my part correctly.

I have COL issues in my 9mm compact as well. Recommended COL for my load was 1.142”. These worked fine in my 2.0 Shield, but locked up my Compact. Both pistols are 2.0 with 4” barrels. By trial and error, I found out that for my compact the longest COL that works is about 1.125”. Problem doesn’t seem bullet related. Same problem using Hornady 115 HAP, 147 XTP, PPU 130 FMJ, and 124 Speer Gold Dot.

One thing I learned with 9mm... with any new bullet, first step is to use an empty case and find out the max COAL that will plunk in your gun(s). Then you can look for loads that let you use that COAL or shorter.

PITA checking this for each bullet type on multiple guns, but gives you a necessary data point.

For some reason this was never a problem on 45’s for me.

I can sure agree with that! I've found that .45 Auto and .40 S&W are the most trouble-free to reload. I have 6 1911's and a Ruger P345 in .45 Auto. I use the same range reloads in all of them with no problems. I don't own a .40 S&W anymore, but have owned 4 different ones over the years. None of them game me any chambering issues either and were a wide variety of pistols: Dan Wesson 1911, Taurus's 92 Beretta clone, Springfield XD40, Taurus PT111

That's interesting. I was blaming it on the Sierra bullets.

All I know is that the factory Speer 124 Gold Dot has a 1.12" +/- OAL that works.

I had a test at 1.13" in my 5" and a 1.08" OAL in my C9 3.5" and had malfunctions, with the factory bullet in my two 9 mm pistols.

These test might work in your pistols but it does show that OAL of a load is important.

Many semi-auto pistols are short chambered with little to no throat . Seems more often with the 9mm .

Use data for ANY 124gn JHP for your 124gn JHP. Buy a Sierra manual.
Never had any issue loading 9x19 with any bullet, other than a BHP. Of course, I also always start my reloading session with a new bullet by making over long dummy inert rounds and incrementally seating the bullets deeper until the rounds feed from the magazine and completely chamber.
The BHP had a feed ramp that had a sharp angle up that then abruptly became less angled into the chamber (i.e., it was like a dog leg). It wanted a VERY precise COL or it wouldn't feed. Polished out the transition point and never had an issue again.
Download ANSI/SAAMI Z299.3-1993 or newer version from SAAMI web site.

I follow the same routine as you when using a different bullet. At the time I bought the Sierra 125 gr JHP's, the only 9mm handguns I owned were a Ruger SR9c and an HK VP9. The load data I had called for a COAL of 1.130". I tried the "plunk" test on these 2 guns and found that the rounds were too long. I shortened the length to 1.210" and that worked in both guns. I test fired them and had no feeding issues. Later I bought a Ruger 1911 Commander sized gun, and again, no feeding problems. Next up was a Sig P365. Again the loads worked fine. Then I bought the M&P 2.0 Compact. Should I have checked before going to the range? Yeah, probably, but who would have thought that after they worked in 4 other 9mm handguns, I would have had a problem? (I also have an M&P 9mm Shield, but never tried the reloads in it.) Back to my original point - this has only been a problem with 9mm pistols. In the last 45 years have reloaded thousands of .45 auto, 40 S&W and .380 Auto rounds for a number of different guns in those calibers, with no feeding problems due to COAL. The 9x19mm is the most popular caliber in the world, but it's still a stinker if you reload for a number of different guns.

Maybe if I had access to a high grade optical comparator I could see the difference in profile between Winchester's 9mm .355 115 grain FMJ hollow base bullet WB9MC115 and its flat base counterpart WB9FB115, but I can't. Loaded identically, the flat base version gives problems in some pistols, the hollow base version doesn't. Changing the COL trying to find the magic number that will work with both bullets in all the guns has eluded me.

I simply gave up and use the hollow base bullet exclusively when I can get it.

Sounds like a plan to me.

Wait until the bullet manufacturer changes the swaging mold without notice and your old COL no longer works.

So True !
It may be a PITA to check for each bullet and for each gun but it's the only way ... If it doesn't plunk in your gun's chamber ...
It isn't going to work .
Forget any magic measurements with magic measuring tools and get back to basic old school reloading .
Gary

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