Ran some loads using a Speer 165 Gold Dot HP through a Kimber Stainless Target II 5" and a PARA-USA Elite LS Hunter 6".
5-shot average
AA-9: 14 grains
5": 1216
6": 1276
About what one would expect from an extra inch of barrel...now it gets strange....
Power Pistol:
9.0:
5": 1289
6": 1295
9.5:
5": 1296
6": 1284
10.0:
5": 1303
6": 1276
I have never used PP before buying the 10mms and bought it mainly because of the data I've seen showing it one of the better powders for the round...but this is a little strange... And all the loads had a very low ES so it it isn't like a low shot brought the average down...
Thoughts..Bob
Is a bit odd.
#9 is slow, so one would always expect (to a certain point) that additional barrel length = higher velocity.
PP is on the fast side, but still...
I'd have to guess the Para just has a slower barrel. Have you done any other direct comparisons?
That just doesn't seem right for the longer barrel to come in with slower velocities.
Two things come to mind though, actual bore diameter and freebore throat.
I think I read somewhere, that Kimber was using a 0.3990" bore which was on the tight side. This would have less blowby.
Many barrels are at 0.4000" and some bullet have blowby more than others.
The freebore throat is where the bullet makes its jump from casing mouth to the start of the rifling, in pistols this can also have some blowby with longer throats. Those with shorter throats can see more pressure and better velocity gains.
It all goes back to the old saying..."No Two Guns Are The Same!"
Seems like another great example of why, when anything changes, we work the load back up :)
I hope you proceed safely.
I have a better question. How much faster in my Mechtech 16" barrel? :P
Yup, the other posters nailed it. I recently chronographed two of my 30-06s using the most accurate handload I have come up with thus far. The 22 inch Xbolt clocked in at 2857 fps and the 24 inch Model 700 averaged 2834fps.
The difference between the two barrels? The M700 has a crazy long throat which I believe is the reason for the slower velocity. In essence, a firearm is a pressure vessel. When you make the pressure vessel bigger by having a longer throat, there is more room for the gases to expand. Since the expanding gases have a bigger area to work within, the pressure is lower and the velocity is decreased.
That's my story anyway. It's rifle related but pistols aren't much different...they're still a pressure vessel.
Primers?
I noticed my mag primers (cci350) gives better velocities than WLP......
14.1 No .9 w/ 165 FP in Glock 20 4.6" bbl - 1240.
Quote from: sep on October 13 2016 08:59:45 AM MDT
Yup, the other posters nailed it. I recently chronographed two of my 30-06s using the most accurate handload I have come up with thus far. The 22 inch Xbolt clocked in at 2857 fps and the 24 inch Model 700 averaged 2834fps.
Reminds me of when I tried some Remington 30.06 saboted accelerator rounds through my deer gun, just because I liked the warp speeds it was supposed to throw them projectiles. Accuracy of them rounds was absolutely putrid. I was all over a target at one hundred yards. I popped in one of my regular reloads, bang! Hole dead center in the bullseye. That was the day I decided velocity was way way down on my list of what I was trying to achieve with my reloads. This was followed by noticing that the higher ends of all my recipes was not condusive to accuracy, the faster they were going, the less accurate they became. Therefore I search for the most accurate loads, not the fastest.