Barrel Twist, Bullet Spin with 115gr 9mm Question

Been thinking about loads for the 9mm RO that I bought as a project gun. Spent some time looking at posts on here about it (any idea why we can't search for "9mm"?).

From what I've read, 115gr bullets don't seem to like to be spun up too much as they like 1:32 barrels. 

My question is what is the relation between twist, load, and bullet rotation. The math in my head says that lighter loads with the same twist barrels gives less bullet spin than hotter loads. Just curious as to what I might be missing.

My mentality is to use 147s LL and 115gr SL. Use 147s since my 1:16 works better in them. Then use 115s SL for powder puff loads. 

In case something I've said hasn't made it obvious enough, very little knowledge about 9mm loads.

9mm +loads

I built a 1911 in 9mm and put a KKM 1/24 barrel in it and it was great. If I ever have to replace my 45 barrel I'll do it with a KKM. They seem to be good barrels.

My 9mm RO loves 6.4gr Power Pistol  and 115gr JHP. That's pretty hot. Should work in yours.

people are far too concerned about twist rate. The 115XTP doesn't care. Get the 115XTP and N330 powder. problem solved. it's all about the bullet and powder not the twist rate. twist rate mattered with round nose bullets.  

the AMU shoots an 18 twist barrel now with, OMG, the 115XTP.

https://kkmprecision.com/product/9mm-natl-match-amumarine-corp-1-18-twist-2/

My gunsmith talks with KKM regularly. Kevin stated the AMU has not ordered 32 twist Beretta barrels in years.

buy the right bullet and make it go 1100fps with N330/340, then add trigger control.

HAP and Zero work great too. Nosler not so much an accuracy problem as a feed problem. Two of my 9s don't like them so I just quit buying them.

LenV wrote:Nosler not so much an accuracy problem as a feed problem. Two of my 9s don't like them so I just quit buying them.

Len want to borrow my grinder and fix that little problem?

I did fix the problem. I took them out of the queue . The problem I had with Nosler is they don't fold the jacket over the nose. The resultant sharp edge tries to stick into everything. Reminiscent of the obsolete  Flying Bucket.

LenV wrote:My 9mm RO loves 6.4gr Power Pistol  and 115gr JHP. That's pretty hot. Should work in yours.

My 16 twist Barsto barreled Beretta loves the same bullet at 1100fps. My 1911 with a 32 twist loves the same bullet or any 115 grain bulllet with Power Pistol at 4.8 grains for the shortline. new meaning to the term "powder puff". barely lifts above the black. I still use the XTP at 1100 for the 50 yard line. clover leaf's when I do my part.

It's pistol shooting no math needs to be involved. It's not the Army Math Unit.

let's get passed these old wives tales that somehow twist rate makes a marksman a master or vice versa. we all know what makes a master class shooter.

Any opinions on if there will be an AMU switch to the new Sig with its 1:10 twist barrel? Or will they just stick with a Beretta or 1911? Perhaps if a striker fired pistol can be made Bullseye worthy. Those fast twist Sig and CZ's really like the 147 gr XTP at about 925 fps. Much faster than a .45 and soft shooting..

From recollection SFC (ret) Patrick Frank’s shot a highly modified Sig for Bianchi Cup and won the class. The Beretta has a much better receiver for rail modifications than the Sig. I would guess the AMU won’t stray far from the Beretta unless something or someone pushes them in that direction.
Jon

tovaert wrote:Any opinions on if there will be an AMU switch to the new Sig with its 1:10 twist barrel? Or will they just stick with a Beretta or 1911? Perhaps if a striker fired pistol can be made Bullseye worthy. Those fast twist Sig and CZ's really like the 147 gr XTP at about 925 fps. Much faster than a .45 and soft shooting..

At the 2020 Phoenix mid winter the AMU were using Beretta's but the link clearly shows they can make a striker pistol work. Froneck stated here that his son used the same 115 gr Atlanta Arms ammo in both the Bianchi Cup and Perry matches. 6th place in the NTI and set a national record in the Bianchi Cup with a XDM. I would not doubt they move to the new Sig just to prove it can be done.  The USMC Reserve team were using them at Canton/Perry in 2019.

https://www.bullseyeforum.net/t8703-springfield-xdm-for-cmp-eic?highlight=springfield+armory

I think the USMC and USMCR teams are using the M18 in their “Division” matches.  I suppose the USAMU will use the M17 in short order.  I also tend to think that with the M17/M18 going services wide there might even be a move towards optical sights even for combat use (perhaps especially for combat use).   It makes sense on many levels.

I know they shoot them. I was there. The SSGT that made the P100 with his also said they didn't shoot bullseye at the Marine Corps matches that year. They have moved on to what they need to do, as they always have.
The Marines at the division level matches have not shot the National Match Course as we know it  for EIC points in over 20 years. They shot rack grade Beretta's and issue ball all at 25 yards. The top shooters earned a trip Quantico and then used 1911's or match 92fs's at full distance. Then they had to earn a dot with a minimum score of 2550.

I guess someone will now question the authenticity of USMC marksmanship. Last I checked they seem to get the job done when it matters.
I used to enjoy shooting rifle with them. Not a word out of them about twist rate or bullet weights or anything and then they post a 100-8x or something at 300 and I'm not talking about a team shooter i'm talking about a guy that worked on tanks everyday. Just pure execution of marksmanship fundamentals all day long. They don't care about the other stuff.

The 9mms I've seen the AMU use locally are 1911s.  I changed over to a 1911 I built with a 1 - 18 twist KKM.. shooting 124gr XTPs. 3.5 gr of titegroup.  Not super soft but not even close to hot..