The Good, Not so Good and the Ugly 9mm range test

I spent about 6 hours at the range today testing different loads out of S&W 952 and a totally stock Range Officer. I was surprised by some of the results, shocked by some and got what I expected from others. I was not surprised that the 952 shot better with the best ammo then the RO. I was surprised that there were quite a few that the RO handled better and was totally shocked when the RO wouldn't keep the 158gr LRN on the paper. The difference is probably between the 1:16 and 1:18.75 twist. I had my hopes up on those 158gr LRN being the go to bullet for the short line for the RO. I have all these targets orientated up and down correctly. You will see both horizontal and vertical stringing. Some ammo just had random fliers. The 158gr LRN in the RO as far as I can tell were all fliers

147 gr Hornady RNBT. I expected better from both pistols.


115 gr HAP: This is my normal round for my 952 and used it to get a baseline.

115 gr XTP: Tried powder other than Power Pistol in case I run out. Notice the RO liked this.

115 gr L-SWC: Trying for economical/low recoil short line load. The 952 didn't like this

115 gr L-SWC different load. RO really didn't like it.

158gr L-SWC This is the same semi wad cutter I use in my 38 special. Only one tested for 952

More 158gr testing. No results for the 158 RN in the RO as grid isn't big enough to show it. I was surprised the RN did as well as it did in the 952. Might be a future there for an inexpensive short line load.

Having fun with the Lee rest and the HAP's

I would expect RO to vertical string because all the RO's I've worked on had vertical play at slide stop pin. An oversized pin might reduce the groups. Thanks for sharing.
Jon

Jon Eulette wrote:I would expect RO to vertical string because all the RO's I've worked on had vertical play at slide stop pin. An oversized pin might reduce the groups. Thanks for sharing.
Jon

Jon, my sentiments exactly although I've been blaming the old (2000 rounds) recoil spring in my 9mm RO for the stringing.  Changing to 14 lbs in 1 lb. increments down to 10 lbs made no difference in accuracy compared to the stock 9 lb. spring.  What size pin would you recommend and would it need fitting?  My new S&W 986 really reveals the shortcomings of my RO but it's kind of an unfair comparison.

Start by measuring stock slide stop pin. Your frame will probably only accept a .200" pin, possibly a .201" pin. I would not modify or alter frame for a larger pin, that's when it's time for a new barrel
I've had some that required minor/minimal fitting to bottom barrel lugs and some that dropped in. I've also changed the link in some cases because it was wrong size. So in reality you'll probably only gain a couple thousandths of lock up, but every bit helps. I'm not a proponent of it, but I've seen pistols that link was slightly too long improve groups because it forced barrel to link lock up instead of lug lock up. 
Jon

Thanks for the data Len.  At what range were you testing?

25 yds. I was searching for a good short line load. The 115 gr Power Pistol load is my long line load.

Len

Jon,  Thanks for the tip. Now I have to go back to the range and play/test some more. RO slide stop pin was an inconsistent .195. Going down to .1945 and up to .196. I replaced it with a Wilson Combat extended slide stop that measures a solid .1995. That seemed to tighten it up a bunch. Back to the drawing board. My next trip I will also take an additional 1911 (45) and test it with different EIC loads.

Len

Unlikely to be twist rate, as the twist rate for 147gn bullets in 9x19 should be 30:1 or faster. 1:16 and 1:19 twist rates are much faster than needed.

Noylj,  I am sure you meant 1:30. Both pistols handled the 147 equally poorly with one pistol throwing the bullets in a circle pattern and the other vertical stringing. It was the 158gr L-RN that surprised me. The bullet has a hollow base and a hardness around 8. This is the most accurate lead bullet that I have found for my DR revolver that also has a twist rate of 1:18.75. I hypothesized that it might be the twist rate because the RO might be putting too many revs on that particular bullet. The groups with that bullet and the RO were in excess of 12" while the 952 would have grouped in the 10 ring. Something was destabilizing that bullet in the RO.

Len

It is more likely to be muzzle pressure.  The 9mm is more like a 357 and a 357 can start scattering because of the higher muzzle pressures.  The cure was to shoot jacketed or to shoot very hard cast bullets.

When I originally saw the post/groups I thought they were 50 yd groups. A slidestop pin change isn't going to effect these much. Either an ammo or rest issue. In my experince 9mm shoots good at 25 yds and becomes belocity critical at 50.
Jon

Both pistols are 9mm. I tried 2.8, 3.0, 3.2 and 3.5 gr Of Bullseye. The recoil was very light on all loads. Too light on lowest load and would not cycle. That is a poor way to measure chamber pressure but when using these very reduced loads it gives you a comparison. The only difference between the RO and the 952 other than twist rate is barrel length. 5" v 6".
  This whole test was to see if I could find a cast (cheap) bullet that would work good on the short line with reduced recoil and less expensive bullets.
   The test showed me that there was nothing I have found (yet) that would be a suitable replacement for the 115gr XTP or HAP that I use already. There were some loads I can shoot while training but nothing that I would bring to match day.
   I don't know why the RO doesn't like the 158gr RN. I do know that I won't be loading anymore of them.

Len

Len,
I have had good luck with 147 gr. flat points, 3.2 Win 231, 1.147 OAL.
Dave

Where do you get your flat points?

Len

The guy at my LGS casts them. Looks sort of like a round nose with a flattened end.
PM me if you care to try a few.

I see Penn has something like that. Magnus site appeared to be down today. I will see if I can find some. Thanks

Len

If you don't let me know. I'll be glad to send some. Thanks for your postings.

If anyone followed Jon's advice (like I did) about putting in a larger slide stop then don't forget that the 9mm has a different slide stop then the 45. The 9mm slide stop has a little bit longer arm on the inside to reach the 9mm magazine which of course is narrower then the 45. I searched the web looking for a good choice and think I found it with the offering from Fusion Arms. The pin measured .2000 (and the price is right). I am only posting this as an FYI. I have no financial interest (NFI) in Fusion Arms. I had to go looking for a 9mm version when the larger slide stop I had in my parts bin tightened it up a lot but would not lock slide back.

Len

http://www.ebay.com/itm/261846098662?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

OldMaster65 wrote:If anyone followed Jon's advice (like I did) about putting in a larger slide stop then don't forget that the 9mm has a different slide stop then the 45. The 9mm slide stop has a little bit longer arm on the inside to reach the 9mm magazine which of course is narrower then the 45. I searched the web looking for a good choice and think I found it with the offering from Fusion Arms. The pin measured .2000 (and the price is right). I am only posting this as an FYI. I have no financial interest (NFI) in Fusion Arms. I had to go looking for a 9mm version when the larger slide stop I had in my parts bin tightened it up a lot but would not lock slide back.

Len

http://www.ebay.com/itm/261846098662?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Hello OldMaster65,

Fusion Arms is not know as a supplier of quality components.  I would be looking at someone like EGW, Wilson, etcetera.

Good luck,

Jim

I had no problem with their SS 9mm slide stop. Right to specs.