STI .40 bullet length

Dan-O-Mite

Dan-O-Mite

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I did try a search on this topic, but nothing came up, so...


I just got my first STI pistol, the DVC Limited in .40 . I had it at the range today for the first time, and although it functioned perfectly, accuracy wasn't great. I even had a few bullets tumbling. I've heard that STI guns load really long. I was using Campro bullets loaded around 1.17" - 1.18", with 5.2 grains of Titegroup.

This is the same set-up I use for my Tanfoglio LC and it is pretty accurate, definitely no tumbling.

I've had lead bullets tumble on me before in a 9mm Taurus, but never plated or jacketed.

I'm hoping that my issue can be easily corrected with an adjustment to my bullet making. At 20 yards ,out of every 10 rounds, about 5 went where I expected and the rest were a couple inches out, or tumbling and barely on the paper.

Any other ideas on what might be happening? I really hate to think it's the gun....... (like really really hate to think that).
 
How many grains the .40 .i have sti .40 as well load tight group 4.2 graint for 180gr bullet JHP .lenght at 1.187 .i use to load at 1.18 and had major FTF issues
 
I don't know if you need to load that long - it's a bit of trial and error. In my STIs the OAL I use is 1.160 in .40.

How is your crimp? I found that my STI pistols are sensitive to over-crimping. I only crimp enough to remove the flare and pass a chamber-check, no more. Jacketed are less sensitive than plated.
 
I use 180 grain bullets. The crimp is not excessive, just enough to straighten the case side wall. Like I said it functioned perfect, no failures of any kind. Just accuracy issues.
 
I load 1.18 in my Apeiro, but use e3 rather than Titegroup. Have you tried posting this on the Enos forums?

5.2 grs sounds like a pretty hot load using Titegroup - well beyond what Hodgdon lists as max. Maybe back it down .5grs?
 
Load sounds a bit heavy and the difference in the style of rifling in the two pistols is something to consider.
 
I'm using the 5.2 grains of Titegroup in order to make major power factor for IPSC. In my Tanfoglio it makes about 176 power factor. I have no issue with changing my loads, as long as I make the power factor.
 
I'm working 12 hour shifts until Friday, so I won't have a chance to test anything until then. I do have some jacketed BDX bullets to try, along with the Campro. I'll load up some at different lengths to try as well. Beyond that, not sure what else to try.
 
Well I finally got to the range tonight. I used Campro and BDX bullets at 1.160", 1.180", and 1.200". The 1.160" had 4.9 grains of Titegroup, the longer lengths had 5.1 grains. Everything worked fine. I didn't get any bullets tumbling like the other day. I was shooting at 15 to 20 meters, groups were good with an occasional flier that was likely my fault. I was just shooting off hand, not using any rest. I don't know what was causing the issues the first time out, but I hope it's the last time it happens. Thanks for all the input from everyone.
 
Tumbling of bullets is often caused by over crimping..use 4.8 gns of titegroup 180 grn campro you will be ok..ive had all sti ,limcat and svi with out any issues
 
Raymond, glad to see your trojan bull barrel is getting some action ;) , feed it some 200gr for one shot and try it, at the time it definately liked it more

As lots of people have had this problem with campro and over crimp.
Was running 200gr. and 4.6TG to make 176PF in an STI bull barrel. I had to keep crimp in .421'' spec, as soon as i was in the .417-.418 range i would get a shotgun pattern one shot out of 15-20. I could call my long shots and get a miss, and then find bits off shrapnel had made it to target and some on the ground. .421'' crimp was my magic number with campro
 
MartyK2500 said:
Raymond, glad to see your trojan bull barrel is getting some action ;) , feed it some 200gr for one shot and try it, at the time it definately liked it more
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Hey Marty:
I have some 200gr made with the specs you had sent me. I just haven't ran any through yet. Might do that tomorrow. The 180 seem to feed great and fire very nice. I am very happy with the way everything is going.
 
Dan-O-Mite said:
Do you shoot IPSC? I find it hard to believe that you can make major power factor with only 4.4grains of Titegroup.
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4.4 won't even be close. Same as you, my Tang Limited Custom takes 5.2g of Titegroup on a 180 RN just to get 170 pf, which is not enough for Major PF. I needed to bump mine to 5.5 to get a consistent 180 PF
 
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