1911 9mm Softball Accuracy

In a couple of earlier threads I have posed the question of whether a 9mm 1911 shooting light target loads can be made accurate enough for CF Bullseye use.  I know that very accurate 9mm’s are routinely built for hardball, but they typically require hot loads to achieve accuracy.  This is a different proposition.  In essence my question was this:  Since the 38 Special 148 wadcutter load at 700 fps is both light in recoil and highly accurate out of the 10 and 12 twist barrels often used in PPC, why wouldn’t a 147 grain bullet of essentially the same diameter (.357 vs. .355) pushed to 700 fps out of a 9mm casing also be accurate if a 10-12 twist barrel were used?

Answering this question experimentally requires building a target 1911 on a 9mm with a 10 or 12 twist barrel.  Such barrels do not exist so far as I have been able to determine.  So I undertook to sleeve an existing 9mm barrel using a 12 twist sleeve.  Jerry Keefer was kind enough to donate a section of high quality 9mm Douglas barrel blank with a 12 inch twist rate.  I used this to make a sleeve and bored out an existing barrel to fit the sleeve.

My sleeve was designed with a large diameter at the chamber end for two reasons.  First, I wanted a shoulder on the sleeve to resist bullet forces from dragging the sleeve forward and causing it to loosen.  Second, the barrel carcass I used was loose as a goose in the hood area.  Using a large diameter sleeve provided me with the material to re-mill the hood and get a good fit in the slide.  This should show in one of the pictures.  The sleeve was installed with Loctite 620, chambered, the hood and extractor groove milled, a feed ramp cut, and given an 11 degree target crown.

The “new” 12 twist barrel was then carefully fitted in both the hood and lower lug areas and a new bushing was also carefully fitted.  I had previously done a trigger job on this gun and tightened the slide.

I am continuing to test this “fast twist” 9mm and to try new loads, but I believe the results already demonstrate the relative success of the proposition.  My load of 2.5 gr Bullseye behind a 147 gr Hornady XTP are giving 10-shot 50 yard groups in the neighborhood of 2.5-2.8 inches.  This load clocks only 730 fps on my chronograph and is light in recoil.  I shoot .45 in the CF matches, but for those desiring a softer recoiling CF gun, the 9mm could provide an answer if only some fast twist 1911 barrels were available……

I enjoyed this project.  I hope you find something useful in it.

In the interest of full disclosure:

1.  Although I like to tinker in the machine shop and have built a half-dozen or so 2-2.5 inch .45’s over the years, I don’t have the experience of building literally hundreds of target guns that real gunsmiths like Jerry, Jon, K.C, and others have.  If any of them had done this work they may well have knocked another inch or more off the group sizes.

2.  The 50 yard groups shown were all fired carefully over sandbags using a frame mounted 1” Ultradot. If I had access to a Ransom Rest I feel they would be somewhat smaller still.

3.  The test gun was built on a lightly used Citadel 9mm (Philippine).  I would not choose such a platform for a gun I expected to hold up for 30,000 rounds.  But this was an experiment to prove a point, and it served well enough for that at relatively low cost.

4.  You won’t find the loads I used listed in any manual; they are too light.  I stuck to fast powders like Bullseye and kept reducing the load to get down into the neighborhood of 700 fps.  Use any of this strictly at your own risk.


5.  All testing was with jacketed bullets.  I don’t use much cast or swaged lead.  Someone else will have to do the lead bullet testing.

I am impressed Don.. Great groups, especially hand held..Excellent work.. Thank you for your efforts..An old shooter once said to me.." Define over stabilization for me."  I firmly believe fast is better than slow, it's better to be faster than necessary, than to be too slow..  That's why slow twist 148 HBWC  leaves yaws marks on the target.  Here's an old target I had hanging on the wall and could quickly grab.. I am posting it, because, I think some people don't believe that a 38 can shoot that good.. This is the 148 HBWC by AMI..and all 24 will score  B-6  X ring..

TRY 4.0 WSF WITH THE HORNADY 147GR XTP. SHOULD SHOOT 1.5 AT 50 OR LESS . THAT IS WITH YOUR RATE OF TWIST. 900 FPS WITH A 5"BARREL. AOL 1.142 I RAN A 14 -15LB RECOIL SPRING. JIM P

Awesome project.  Very nice. Love to see people break out of the norm. Very encouraging! Thanks
Jon

Nice work Dr.Don to what appears to be the beginning of a long conversation on 9mm for BE at velocities proven to be effective with other calibers.

Edit:
Is there a way to determine a theoretical preferred stability of a bullet based on bullet geometry, weight, barrel twist rate, velocity, etc?

Beeser,

  Have you read this? Go to

www.schuemann.com   Then go to Documentation. Then go to Barrel twist information.  I tried to create a shortcut but failed miserably. Good reading.

ultimately, as they say, the proof is in the pudding.....

OldMaster65 wrote:Beeser,

  Have you read this? Go to

www.schuemann.com   Then go to Documentation. Then go to Barrel twist information.  I tried to create a shortcut but failed miserably. Good reading.

Thanks!  Not the theoretical treatise I was looking for but interesting nonetheless.  Also interesting that Schuemann's optimum twist rate for 1911 barrels (9x19 included) is in the opposite direction of what Dr.Don is finding to be accurate.  I'm confused.  Dr.Don - Did you select the 10-12 twist rate based solely on the PPC success with it and simply wanted to duplicate the results?  Or was there some theoretical push in that direction?

Schuemann was optimizing light weight bullets, don is duplicating the highly successful .38 special loads, only in 9mm. Imho

Jerry Keefer wrote:I am impressed Don.. Great groups, especially hand held..Excellent work.. Thank you for your efforts..An old shooter once said to me.." Define over stabilization for me."  I firmly believe fast is better than slow, it's better to be faster than necessary, than to be too slow..  That's why slow twist 148 HBWC  leaves yaws marks on the target.

Jerry - Isn't it equally possible to destabilize a bullet by spinning it too fast?

beeser wrote:

Jerry Keefer wrote:I am impressed Don.. Great groups, especially hand held..Excellent work.. Thank you for your efforts..An old shooter once said to me.." Define over stabilization for me."  I firmly believe fast is better than slow, it's better to be faster than necessary, than to be too slow..  That's why slow twist 148 HBWC  leaves yaws marks on the target.

Jerry - Isn't it equally possible to destabilize a bullet by spinning it too fast?

I am sure there is a practical limit. But 10/12/14 twist has been used for decades and has been very successful with 38 caliber projectiles.  I am all for innovation and going where others have not..But one thing to consider.. Each projectile has an inherent accuracy potential.. Achieving accuracy that is near that potential, means something is being done correctly.  I have gotten some outstanding 45 ACP groups from the 1911 using a 14 twist Douglas barrel.. Far better than I have ever gotten with a 16 twist..I want to try 12 twist next.. Time is the issue..Theory and reality are often not the same.
Douglas barrel/14 twist/15 shots

The reason for the 10 thru 14 twist being chosen, is that the early smiths building ppc guns used 35 cal rifle blanks. IIRC the python had a 14 twist and there were some smiths who put python barrels on S&W K38s and got good results but not as good as the customs. One other thing that the python had was a different forcing cone and that was also found to be better than what was on the stock Smith barrel. So the difference in accuracy was a combination of twist and forcing cone.

OldMaster65 pointed me in the direction of Schuemann earlier to answer some of my questions.  All of their barrels begin with a maximum 16" twist rate with a suggested optimum of 24", which seems to be at odds with the findings here.

There was no theory driving my experiment.  It was all based upon the success of the 38 Special wadcutter load in faster twist barrels, and the similarity of the calibers and bullet weights for the 9mm.

beeser wrote: Schuemann...  their barrels begin with a maximum 16" twist rate with a suggested optimum of 24", which seems to be at odds with the findings here.

Next time you are at a large match, Perry would be fine...Take a survey of the top shooters and see what barrels they are using... The "odds" will continue. There are smiths that spend 99% of their waking moments, conspiring to improve the accuracy  of the 1911.. Most of the "frontiers"  have been conquered. The AMU is a good example.. and the reason they are winning everything in sight.. The barrel remains the challenge..The twist should be faster. Slow twist is for patched ball muzzle loaders...

Jerry Keefer wrote:Next time you are at a large match, Perry would be fine...Take a survey of the top shooters and see what barrels they are using... The "odds" will continue. There are smiths that spend 99% of their waking moments, conspiring to improve the accuracy  of the 1911.. Most of the "frontiers"  have been conquered. The AMU is a good example.. and the reason they are winning everything in sight.. The barrel remains the challenge..The twist should be faster. Slow twist is for patched ball muzzle loaders...

What twist rates are they (top shooters at Perry, AMU, etc.) using in their 1911s?  What barrels?

Schuemann barrels seem to be well respected.  It's at least interesting that all of their offerings in barrel twist rates start at a conventional 16" and work toward a slower 32".  They apparently have a lot riding on slow twist.

If you intend to talk to an AMU shoother ask him about shooting, not about gunsmithing, reloading or anything technical. They simply don't know. I remember at Perry when after the school they had a number of top shooter on stage to answer shooters questions. Zinns was asked about reloading while he was still a Marine shooter. I've long forgotten his exact answer, it made everyone chuckle but essentially he had no idea he shoots what given to him with the ammo supplied. If you have any technical questions wander over to one of the trailers at Perry and ask the Armorer. About the only thing the AMU shooter can do is adjust the sights!

Froneck wrote:If you intend to talk to an AMU shoother ask him about shooting, not about gunsmithing, reloading or anything technical. They simply don't know. I remember at Perry when after the school they had a number of top shooter on stage to answer shooters questions. Zinns was asked about reloading while he was still a Marine shooter. I've long forgotten his exact answer, it made everyone chuckle but essentially he had no idea he shoots what given to him with the ammo supplied. If you have any technical questions wander over to one of the trailers at Perry and ask the Armorer. About the only thing the AMU shooter can do is adjust the sights!

My reference to asking or surveying the brand of barrel for the .45 was meant to indicate, as many here would agree, that the predominant brand is Kart 16 twist..and probably KKM as runner up.. I have never had a shooter Marksman or HM ask for any other..

Though I'm a 45 shooter and prefer it I did fool with the 9mm for a while. I agree Kart 16 is the best, never used the KKM.
 Though I would mention questioning Military shooter and think they were trying to avoid answering! They want to keep the secret to shooting to them selves!
 Hmmm maybe I can get a web page, sell some secret herbal solution found high on the Mountain tops in Peru that will make you a High Master is 2 matches. $29.99 Buy it now before they make me remove the web pages!!

I hope this fits this thread.

I'm fitting up a Kart 9mm barrel today. The throat is quite short, apparently intended for factory Ball ammunition. When I try various bullets seated at various lengths, (such as the Hornady jacketed bullets) I find myself wondering if a little lengthening of the throat would be a good idea.

The Hornady bullets will need to be seated very deeply to fit the throat and deeper than I'd like for best feeding. Many cast lead bullets may benefit from a bit more room in the throat allowing longer overall cartridge length for better feeding. But, I'm really looking to shoot 95% lead in the gun. I don't have a 9mm mold at present and I'm thinking about one of the 140 SWCs that sort of resemble the #68 H&G in .45.

All that said, does anyone have experience with variations in 9mm throating? And maybe the cast lead bullet you found to be best in 9mm?

I don't like or want the rifling leade to dictate the seating depth.. An auto pistol will eventually have cycling issue. I have all my reamers ground with some freebore.. I believe accuracy is improved, much of the abrupt, peak, ignition shock is reduced, as the projectile gets a running start into a 1-1/2 degree leade.
I might add, that leading is also greatly reduced, since the bullet is gently introduced to the lands and grooves, as opposed to the higher pressure required to engrave the usual 5 degree leade. The less the projectile is distorted or deformed the less lead transfer, and better accuracy.

Jerry, thanks for your helpful response.

Would you think a .030" X .359 or .360" free bore transitioning into a 1.5 degree throat is about right? (I'm thinking about .358" lead bullets but have not slugged the bore yet, so maybe smaller) Is that in the neighborhood? Would you mind sharing your reamer print?

Kart barrels all have a short throat, good for ball but problem for anything else. Since I only shot ball in the 9mm I had no problems but I made a hone for the 45 and used the 1.5 degree throat angle. I was surprised as to how well it shot lead afterwards Jacketed seemed to improve too. Being a Wad gun I never shot ball with it.
 My hone for the 45 as simply a turned blank to match the chamber with a 1.5 degree taper on the end, some undercut so the lapping compound would not cut any more than I intended then a pilot that fit the bore for alignment. Some undercutting on the chamber side of the taper too and a shoulder so as to let me know when the hone was at the depth required. Didn't take long to lap and the surface was very smooth.

HenryA wrote:Jerry, thanks for your helpful response.

Would you think a .030" X .359 or .360" free bore transitioning into a 1.5 degree throat is about right? (I'm thinking about .358" lead bullets but have not slugged the bore yet, so maybe smaller) Is that in the neighborhood? Would you mind sharing your reamer print?

I run more than that.. .075/.100 is not excessive. A revolver Taylor Throat freebore section is the length of the 148 HBWC projectile..which is about .625 It's best to determine exactly what projectile you are going to use, and make the diameter to compliment that diameter.. For example: In 45 we only use PENN Bullets @.452 and that is the freebore diameter. The expanding gas pressure speed is much faster than the projectile ever reaches, and passes the projectile for a nano second, before the bullet actually moves into and seals the bore.. Some theorize that the expanding gases, which exert forces equal in all directions, tend to center the projectile as it enters the freebore and leade during the internal ballistic period. One ballistic scientist once wrote, " We know a great deal, about what actually takes place internally, during the ignition event, but we don't know everything exactly."

Got the new barrel fitted up and found a reamer for a 9X23 Winchester. I bored out a small stub of barrel to fit the pilot and made a test cut to see what the throat dimensions were. My best measurements of the cerrosafe cast showed it to be a straight cylinder of .358" diameter by .040-050" long then tapering to bore diameter at about .150" out. Calculates to approximately 1.5 degree taper.

I used that reamer to cut the new Kart barrel. (but held it shallow to give tight 9X19 head space) The resulting throat gives room to seat the bullets out a bit and make for good feeding from the 1911 magazine.

I shot it last Saturday standing in 3 inches of snow and leaning arms against a tree. Got a 1 5/8 by 1/916 group at 25 yards using Hornady 147gr. XTP and 4 grains of WSF. More testing to come for sure as I want to shoot my own cast in it.

I'm looking at a couple of different molds from Accurate Molds. I'm attaching one here for comment. What do you think about that bullet?