Slow barrels?

[boo radley]

Holy cow -- I've been raving to anyone who'll listen about this used 6" SV I bought a few weeks ago. Needle accurate and a joy to shoot, and SUPER soft. Well, it doesn't diminish the joy any, but I found out why it's so soft. <grin> Despite the 6" barrel it's running about 30 fps slower than my 5" STI build, depending on the bullet.

Just got back from the chrono, where I worked up some loads for a 165 gr bullet. My guess at the high range was 5.1 n320. Not even close with either gun: STI 900 fps and SV 888 fps. For a benchmark I tried my 'standard' major load a 180gr bullet over 4.6 of TG. With a Ranier JHP this usually runs ~173 pf. STI: 965 and SV 931.

Weird, no? Wonder if the STI is just fast, or the SV barrels run slow?

[HSMITH]

Every barrel is an individual, and you don't know what speed it will run until you shoot it. Throat depth and things like that are a factor too.

The extra powder won't make any practical difference in felt recoil, a major load is going to have basically the same physical amount recoil from one gun to the next provided the same powder is used. Think of it this way, using a nominal 5 grain charge if you need another half grain of powder with 180 grain bullets the total ejecta will be 185.5 grains instead of 185. Less than one half of one percent difference in the mass of the ejecta, and that is where recoil is generated for all practical purposes. The 'rocket' effect is minimal with fast powders in 40, and even less of a factor with the 6" barrel.

The short version is put enough powder in it to make major and you are good to go, it really doesn't make a difference.

[Chris Keen]

Shorter version:

If you get a new gun ...... take it to the range and chrono it ASAP, cause you never know. And none of us wants to go minor at any match we plan to do well at (which should be all of 'em)

[boo radley]

Thx guys....Howard, I understand (kinda) what you're saying and will take what I don't understand on faith. It was just startling to realize not only would I not be dropping the charge a couple tenths, as I'd imagined, I'll need to *add* a couple!!

Heh -- last weekend shot her at a steel match using some 40 minor I have on had, which is around 145pf in my G35 and STI....No wonder the cycle would barely cycle, and there was a noticeable *pause* between firing the far steel ringing on stages like "Showdown." Disconcerting as all hell.

[L9X25]

Every barrel is an individual, and you don't know what speed it will run until you shoot it.

+1

Two consecutive barrels from the same machine can be significantly different.

Barrel brand, length and type frequently mean less than the common barrel to barrel variation.