9mm Accuracy & Velocity

First topic message reminder :

Everything that I've read on this forum indicates that 9mm has to be pushed fast to be accurate.  Why is this when .45 ACP and .38 Special seem to perform fine at much lower velocities?    This doesn't make sense to me.

Ouch. Sorry.

-Ron

r_zerr wrote:Ouch. Sorry.

-Ron

I hope you won't be deterred from continuing your thoughts on the subject as this type of thinking is probably needed in solving the mystery of 9mm accuracy whether we understand it or not.

Over at TargetTalk there are some very good discussions on loading for .32 ACP.  The relationship between bullet and barrel diameters coupled with case sizes have a significant impact on performance and accuracy.  I wonder if part of these techniques and solutions could be transferred to loading for 9mm considering that both calibers seem to suffer from a similar variety of specifications.

FWIW, and not really intended for BE, but I just tested an 1184 fps 115-gr JHP load that went about 1.5 inches at 25 yards with irons.

That gun still needs some final work on the barrel/slide/locking block fit. I just might find a way to get that done in the next few weeks. Fixed sights right now, all five just below the black nicely centered at 6:00, and the tightening will probably push the group another inch or more lower. Then I get to look at new sights...

beeser wrote:

r_zerr wrote:Ouch. Sorry.

-Ron

I hope you won't be deterred from continuing your thoughts on the subject as this type of thinking is probably needed in solving the mystery of 9mm accuracy whether we understand it or not.

Not to worry, I will keep on.  It is too interesting a topic and perhaps I was misstated, or was misunderstood, or that I misunderstood what another poster wanted to make a point of.  I do think that what I mentioned are contributing factors, and I also think that the quicker twist rates make things more and more viable. What I really want is more time and opportunity to carry on more of these experiments myself. But until then, I have to rely on efforts of a lot of other very competent folks on this list.

It is Camp Perry time for me, but again this year, it is chasing it in Hi-power rifle, so that is where the effort is right now.

-Ron

With this discussion of 9mm velocity and accuracy I had to dig out my test target for the load that I have settled on through my Salyer 92FS with a slow twist 1/32 KKM barrel.

Not too fast, not too slow, just right for me.
I do not care about why, just what works.

This load and target was shot from my hand, not any form of a rest with an approximate 1130 fps as per the Lapua load manual(I do not have a chronograph anymore cause I shot it and it did not work, so I shot it again and it still did not work, so I gave up on using one )

The pic should come out good enough to read the data but it is Sierra 115gr Tournament Master FMJRN bullets over 4.8gr VV N-340.

30 shot test group with first ten shots to the right, made a click adjustment to the left and fired the next twenty rounds.(yes, a 50yd target at 50yds)

Clarence

For those who don't think a 1911 9mm won't shoot well enough, I shot a PPC (NRA) match at Taylor, Michigan. While there (shooting badly) I witnessed milt Williams shoot a 1480-95x with his S.A custom shop 1911 with the 1-32 barrel.

We just have to keep working at it..

Jim

It's not that 9mm won't shoot good enough,  it's the recoil from the higher velocities to get it shooting well. I build ppc pistols in 9mm shooting 1" range and 1490's. Just finished a .45 PPC pistol with much less recoil and you can see hits at 50 yards with naked eye. It's a barn burner! The .45 is easy to reload for and doesn't take a lot of effort to get it to shoot well. Can also use brass over and over again without having accuracy problems. 9mm requires much more time and effort. 
Jon

Exactly, Jon....
David Sams has minus 1 inch 9mm targets all over the place, from the 1911 platform...I had two policemen set the two man team National PPC record in 2001 with a pair of long slides shooting AMI 147 grain Hornady XTPs from 16 twist barrels.. ... That record stood for 10 years.. The 9 will shoot. Accuracy has never been a problem.. But there is a price, as Jon clearly states. I am anxious to hear about that 45.. .

milt tells me his has to run "hot" to get the results.

It's like you and Jon say.

The question remains: Why?

I was a teenager and noticed that it *seemed* that the smaller the bore, the easier to get great accuracy (then defined at rifles 1 MOA, pistols the magical 1" at 25 yards).

Except for the .45 ACP in the 1911. Guess that we have a few other pistols that can toss those slugs out with 2 inch accuracy at 50 yards at all sorts of slow and moderate and even fast-for-caliber velocities...

Top accuracy with 9mm seems to be from tuned 1911s, tuned Berettas, and a few Euro guns of various types from old-school SIG P210 to newer plastic framed jobs. Is anyone getting any of these to hold the X at 25 with a 1,000 fps 115 or 124-gr 9mm load??? How slow can the 147s be driven with Precision Pistol accuracy???

I think that one of the reasons for the apparent lack of accuracy in the 9 has been because the ammo and bullet makers haven't had the demand for accuracy like the 38 SPL and 45 acp has had.  There are some guns that seem to be accurate enough for consideration.  I have a friend who has a HK P30 that groups very well.  So a 9 can be accurate.  

The ammo and bullet makers need to develop accurate bullets in 9.  There aren't many to choose from.

As I have shown in my thread on the subject, my 9mm gives very good accuracy at 730 fps with the 147gr XTP, but it is with the custom 12 twist barrel.  Recoil is quite light.  But, in line with the comment above about bullets, the XTP is the only bullet I have found so far that consistently gives excellent accuracy in this gun.  The Hornady 147 RN is close but not as good.

Dr.Don wrote:As I have shown in my thread on the subject, my 9mm gives very good accuracy at 730 fps with the 147gr XTP, but it is with the custom 12 twist barrel.  Recoil is quite light.  But, in line with the comment above about bullets, the XTP is the only bullet I have found so far that consistently gives excellent accuracy in this gun.  The Hornady 147 RN is close but not as good.

I did a search for the thread you mention but haven't found it yet.  Could you point me in the right direction?  Will it provide load data, etc?

I second Beeser's request for the thread link. I usually have pretty good Google-fu, but I'm not in the mood to use those skillz today.

The experiences with 147-gr 9mms are of some interest to me. I just am not familiar with them, except a box of Win Silvertips a friend bought me almost 20 years ago. Think they ran like 970 fps??? I don't know what is "fast" or "slow" with them or where the sweet spots of accuracy are.

Hornady XTPs?  I fell in love with the 115-gr when it first came out. Ordered a bunch of Hornady pills from Midway, and they were all apologetic that the catalog number we chose had just been discontinued and they substituted these new ones at the same price. Most accurate ones I had ever found as of that time. Now, the Nosler 115s seem to equal them so I just buy what's cheaper at the moment.

Equipment: "9mm Softball Accuracy"

jmdavis got there before I did.  
The link is 
https://www.bullseyeforum.net/t3825p25-1911-9mm-softball-accuracy?highlight=9mm+softball
and the ransom rest data is on the second page. 
 DO NOT expect to get these kind of results with a 16 twist barrel and the 147gr bullets.

I recently built these 3 pistols (top to bottom): Complete build 6" .45 PPC (tungsten guide rod), Complete build 6" .45 PPC standard guide rod, rebuild 6" 9mm PPC (tungsten guide rod ). All 3 Kart barrels.
I shot 2 loads through the .45's; 200 gr Magnus LSWC with 4.0 gr BE and AYSM 185 gr match. For the 9mm I shot 147 gr AYSM match and Winchester Factory 147 gr (can't find box but police load). I'm using 4.0 gr BE for break in load. These pistols are locking up snug. In the future the loads for 25 yards will be reduced.
Shooting two handed 25 yards at BE target I found both .45 loads to shoot with slightly less recoil than the 9mm loads. The reduced loads will be a dream to shoot once the pistols get a few miles on them. The biggest advantage I found between the pistols was the grouping; both the .45's shot much tighter than the 9mm. I consistently clustered the .45 groups and couldn't come close with the 9mm. The 9mm groups were good but never as good as the .45. The .45 seemed more forgiving to shoot as well. The recoil was more of a push than a snap like the 9mm. I shot 300 rounds (100 each pistol). My eyes are not fond of iron sights anymore, but I was able to shoot several 100 - 7X targets with the .45's. A clean target didn't take much effort. I had more scratch 10's with the 9mm. So nothing scientific to share, but my many years of shooting and gunsmithing prove to me that the .45 is the go to gun for PPC. A ransom rest may give you 1" from your 9mm, but the human factor requires much more effort to shoot it well.
Jon

If the answer to the 9mm accuracy issue is faster twist why do the Kart or Schuemer (sic?) match barrels have 1:24 gain twist and 1:32 constant?  Also, why don't the mfg.'ers change the twist to be more accommodating to the barrel's accuracy?  I follow the sonic speed argument but not the twist argument.   Any clarification out there or am I missing something?  I am a 5-month newbie to this game and trying to learn all I can to find the sweet spot for my 9mm RO.  Thanks.

When the manufacturers produce a firearm, it has to be compatible with all SAMMI spec ammunition.
The reason S&W revolvers have maintained the 18.75 twist rate, for many decades.. They will shoot the entire spectrum of projectiles well, but not necessarily with match quallity results. Bullseye accuracy is not the prime mover in after market barrel manufacturing..It is tailored to the masses..

I just acquired a custom beretta 92, kkm 1/32 twist, and some Atlanta arms 115 AMU fmj-hp, This is said to be very accurate but its not low velocity. Not sure what Jim Henderson's 1911 barrel twist is but he shot a 886 in cf with it when I scored him in S.C last year using this ammo.

FWIW a 9mm 147 grain cast bullet over 3.0 grains of WST seems to shoot decent out of a 38 Super.  Shot the group below at 25 yards with mixed brass.    I've always thought that the tapered case of the 9mm cartridge might be a source of low velocity accuracy issues.  What else could make a 38 Super shoot so much better at 700ish velocities?  I'll be back next week with 50 yard groups using new brass..

2004 Low velocity AMI Match ammo 147 gr XTP Hornady
1-16 twist Kart barrel  25 shots/50 yard RR c/c  measurement is .923  This has been hanging on my wall for 11 years, hence the dirt and scuff marks..

Barrel in a barrel fixture or in a gun?

Very nice groups, guys.  I'm still asking why folks say fast twist is more accurate for 9mm than slow twist and match barrel mfg.'ers halve the twist rate of stock barrels.  Just can't get my arms around it.