Problem with tumbling 9mm 147gr boolits

[wellfedirishman]

I loaded up a bunch of 9mm 147 grain boolits (from Missouri Bullet Company) with Winchester standard pistol primers and 4.5 grains of Unique. The boolit is sold as a 'subsonic' 9mm projectile.

Per my load book that is about 900 fps (I am using load data for 130 grain boolits, there is approximate 10% weight difference, but it is well within safety margin).

I shot these in a Govt size 9mm 1911 built, using a Swenson 9mm barrel and a Rock Island 38 super slide and frame. I found that many (at least half) of the boolits were tumbling, hitting the paper square sideways at 15 yards.

The loads fed, ejected and cycled the action fine. There were no pressure signs, and recoil was mild.

I checked the loaded rounds with a calibers, the diameter of the boolit protruding from the case was just under 356 (approx 355.5), and the case diameter at that point was a hair under 380. I thought that I might have been over crimping and squeezing the boolit, but I don't think so. These are the dimensions that my Speer manual say are correct.

When I previously shot commercial 115 grain FMJ 9mm ammo, there was no tumbling or problems, in fact it was quite accurate.

The barrel I used is this: (from Midway)
Swenson Semi Drop-In Barrel 1911 9mm Luger 1 in 16" Twist 5" Government Steel Matte Black
Product #: 465068

Is the 1 in 16 twist too slow to stabilize the heavier 147gr boolit?

Next time I go to the range, I will try the same ammo and boolit in a Sig P226 and a Walther P99 and see if it makes any difference.

Any input would be appreciated.

[runfiverun]

if you had no leading i'd go up to .7 or .8 with the unique.
that should be about max.
but it could be the cure.

[35remington]

When I hear of tumbling bullets my first thought is often that the bullet is undersized.

What's the lube?

How's the leading?

[HighHook]

When I hear of tumbling bullets my first thought is often that the bullet is undersized.

What's the lube?

How's the leading?

I bought 3k of those from Missouri and having the same problem. They are a great design but a no go on short barrels. Maybe loaded real hot would be the trick because they work great when shot in the Marlin Camp 9.

[243winxb]

You need a 1-10 twist

[wellfedirishman]

Thanks guys. Here is an old discussion here on CastBoolits that is relevant. I can't find a direct link to the discussion thread:

http://forum1.aimoo.com/Cast___Boolits__/Wheelguns-Pistols-and-Handcannons/9mm-Twist-Rate-1-482433.html

I will just try the same ammo in other guns/barrel twist and see what happens.

[MakeMineA10mm]

Even though 147s are noted for being "subsonic" bullets, they still must be pushed hard. The history on them, in case you're not aware, is that some very special military units wanted a 9mm load that maximized energy at a subsonic level to use through suppressed MP-5s. Winchester accomodated them and discovered that 147grs could be pushed to high subsonic levels (990fps, IIRC) in the 9mm safely and would provide the highest energy in a subsonic-traveling package. Speed of sound is about 1080fps at sea level, depending on some atmospheric variables, so Winchester aimed for 90fps under, in case the variables made the speed of sound a little lower.

Now, note that velocity, and remember that Winchester was aiming to go as fast as possible while staying under that threshhold.

This means that the 147s were designed to be going in the HIGH SUBSONIC range from the get-go, and little to no thought was given to loading them lower and lower. Doing so results in poor accuracy, as you've discovered, and that has been my experience too. I've never had success with any 147 (jacketed or cast) at under 950 fps, consistently. Here-and-there, yes, but consistently loading a batch of the ammo and trying it in any/all of my 9s, and I need to be at, or preferably above, 950fps. It is a mis-calculation to think that the 147s were intended for Subsonic in the sense that you can load them anywhere from just falling out the end of the barrel all the way up to just under supersonic.

Personally, I really like the fast-twist in the 9mm. It has allowed me to even load the Ly 358311 RN 158gr bullet in subsonic 9mms, but those were some warm loads to get them to hit nose-first...

[35remington]

Slow twist is kinda an odd excuse, given that various 158's are stabilized just fine from 38 Smith and Wessons in 1-18.75" twists at velocities of 700 fps just fine. Even the long, pointy roundnosed 158's.

Not saying such an excuse is impossible; just that something seems quite contradictory.

158's are even longer than 147's and should be poorly stabilized at such low speeds as well at the slow Smith .38 twist if rifling pitch is to blame.

Besides the idea of speeding them up, I'd try a .357" diameter bullet, but such may not be available for sale in a 147. Reason I say that is that bullets of .355" diameter and 124 grains also tumble from some of my 9mm's, and none in that diameter shoot well regardless of type.

[Boolseye]

+1 on the bullets being a little small (diameter, that is)...9mm tumbling is pretty common. Not a very forgiving cartridge.
Try a slower burning powder. AA#7 or something in that range. I find that quick-burning powders exacerbate tumbling. I think that at least .001 bigger than the bore is advisable, however.

[theperfessor]

Have you slugged your barrel?

[wellfedirishman]

Thanks guys for the input.

Update:
I did try some 9mm MBC 147 grainers loaded with 5.0 grains of Unique in my 9mm 1911 1/16 twist, and it was no better. I tried 9mm 125 grain boolits (also from Missouri Bullet Company) with about 5.0 grains of Unique and they worked fine, no tumbling or anything. I guess the barrel doesn't like heavy bullets period.

Interestingly, I tried the 147 grainers through a Walther p99 9mm and they grouped well (within 4 inches at 15 yards shot offhand) even though some were tumbling. I also tried them in a Sig 226 9mm with the same results. The European 1/10 twist barrels do seem better with the heavy boolits. Maybe a hotter load would make them stabilize, but I don't want to overstress these guns.

[deltaenterprizes]

My Lyman #48 manual gives 3.2 gr start and 3.8 max with a OAL of 1.058'' for Unique. They recommend Power Pistol as the best load for that weight bullet.
9 MM Luger develops high pressure quickly because of the small amount of case volume, be careful.
I use 3.0 gr Bullseye with a 147 gr RN in an aftermarket Glock barrel and they shoot great.

[oso]

Same question as theperfessor. Your 147 grain may not be fitting the throat very well. If the projectile has to jump to the rifling it won't help either, so can you seat it out further and still get reliable feeding?

[wellfedirishman]

No, I haven't slugged the barrel, but the fact that it shoots 125 grainers with the same nominal .356 diameter (and from the same manufacturer) as the 147 grainers suggests to me that barrel diameter is not the issue.

The boolits are seated fairly long already. I don't remember the exact figure, but they are longer than average (due to the longer 147 grain pointy boolit).

I think I will just stick with the lighter boolits and save myself a headache [smilie=l:

Thanks for all the input guys, it is appreciated.


Same question as theperfessor. Your 147 grain may not be fitting the throat very well. If the projectile has to jump to the rifling it won't help either, so can you seat it out further and still get reliable feeding?

[theperfessor]

Your original post said you were using jacketed 115 gr bullets. FMJ factory loads shoot fine out of my Hi-Power. And cast bullets of any weight that are smaller than .3575 don't shoot good at all and lead to boot. I shoot Lyman 359430 cast bullets (nominal weight 133 grs but closer to 137 - 138 with my alloy) sized to .3575 - .358 over 7 grs Blue Dot and it's quite accurate. Cast and jacketed bullets are two different animals. Pretty hard to gas cut a jacketed round, but undersize cast slugs can be gas cut and tip as they leave the barrel.

I was quite surprised years ago when I stopped taking as gospel the specified bullet diameter in a loading manual and actually slugged my bore.

[MtGun44]

Most tumbling 9mms are due to undersized boolits. You probably need .357 to 358 diam

Bill

[NSP64]

+1
Fit is King. I just bought a new Taurus Tracker .357 4" Barrel. Barrel .358 chamber mouths .360. Slug the barrel. When trouble shooting anything, only change(or rule out) one thing at a time. If you change too many things at once, you don't know what the fix was when you fix it.

Personally, I think the twist is too slow.

[Gunsmoke4570]

I load a Magma 147gr (JHP shape) bullet sized at .357" in my 9mm. I've shot it in a Hi-Power, S&W 39, Beretta 92, Olympic carbine and a couple other pistols and have had good accuracy and no stability problems. I don't have my data in front of me, but I was only loading to around 900fps. I was pushing this bullet much faster and was having leading problems. I then read an article about 9mm lead boolits and it advised a really hard alloy or slowing down to 850-900fps. I slowed down to that velocity range and the accuracy is there with very minimal leading.

[9.3X62AL]

While the 9 x 19 Luger is kind of a diminutive pistol cartridge, it is much more of a rifle caliber than a handgun chambering--in the context of cast boolit shooting. It runs at relatively high pressures, often uses fast-for-boolit-length twist rates, and has variances of dimensioning in OEM throats and grooves.

My resolutions for these conditions in my 9mm pistols have been to use fairly hard alloys (92/6/2, usually)--soft lubes (Javelina Alox)--and size them to fit the barrel THROATS closely. Also take care to assure that expander plugs aren't more than .0025"-.003" smaller than the boolits you are working with, and LAY OFF firm taper-crimping. Treat them like rifle rounds, in other words.

.357"-.358" is my usual diameter for the 9mms in my safe.

[Dan Cash]

No, I haven't slugged the barrel, but the fact that it shoots 125 grainers with the same nominal .356 diameter (and from the same manufacturer) as the 147 grainers suggests to me that barrel diameter is not the issue.

The boolits are seated fairly long already. I don't remember the exact figure, but they are longer than average (due to the longer 147 grain pointy boolit).

I think I will just stick with the lighter boolits and save myself a headache [smilie=l:

Thanks for all the input guys, it is appreciated.

Quite the contrary. The short 115 and 125 grain bullets may also be skidding in the barrel because they are undersized but you get by with it as they are short and more easily stabilized. I am with the others here in the belief that the bullet is too small. .357 or .358 may be what you need. Slug your barrel.

[Gunsmoke4570]

I just dug out my range book. Magma 147gr boolit at an average of 865fps from several pistols sized .357". Accurate, mild recoil, and no to very little leading depending on pistol (Even in my Glock 17). I use this for general plinking, pins, and steel targets as the heavy boolits still have enough oomph to knock them over. Using a starting charge of Bullseye, Win brass, and CCI SP primers. Functions in my pistols fine, YMMV.

[mstuhr]

Hi Folks,
My cure for 1911 pistols tumbling with Mo. Bullet 147 grain is long load them to 1.175 and use 38 super mags. It worked in the two guns I have that tumbled them bad at shorter lengths.
4.2 of Auto comp shoots good in mine and chronos at 950fps. Both guns tumbled 2 out of ten rounds totally sideways at 15 yards when loaded shorter.

[Tackleberry41]

I have shot 147gr pretty slow and not had issues. Most of the time, its not sizing properly. Gotten plenty of 'factory' cast that were not very good, often wrong alloy, questionable lube. Or just not sized right.

One issue w 9mm is swaging them being loaded. It may measure .356 outside the case, but not down deeper. And you do need some meat on the bullet to engage the rifling and spin. I tried some NOE 158gr 357 I had sized down. left off the gas check thinking, 147gr are usually bevel base they do not flare the case to much. Was just not enough meat engaging the rifling. Gas checks they shoot great, at 900fps out of a 9mm pistol, or 1350fps out of a 357 sig. But I also use NOE expanders.

[fredj338]

I shoot a lot of 147gr cast/coated thru stock Glock & other 9mm barrels. I NEVER, not once have had one tumble & I shoot some pretty low vel loads, even in my stock G26. So I suspect the bullets are undersized, either by manuf or during the reloading process.

[Shingle]

The results I have gotten with 147's and 1x16 in pistols some will some will nott. In a carbine it is good to go that is most likely your problem.

[35remington]

This may be a record for ancient thread resurrection.

The 1-16 twist is most assuredly not the problem.

[twidpa]

Slug barrel and buy accordingly.
T

[35remington]

Match 9mm barrels are overwhelmingly 1-16 twist, and they certainly are expected to shoot 147 grain bullets well. And they do.