Whats going on here?

[freire]

Nosler reloading guide shows.
23'' lilja barrel 1-9'' twist
46.5 gr of RL22
2740fps
...........................................................
Lyman reloading guide shows.
Swedish Mauser m38 24'' barrel
1-7.5'' twist
47 grs of RL22
2576fps.
.............................................................
both bullets are 140 grs
do you guys think that 200 fps difference is possible from a different barrel?

 

[KDX]

Some may be faster. Does elevation or atmospheric conditions affect velocity?

 

[Fassteel]

manuals

Manuals are guide lines to help with reloading a given cartridge. Their accuracy when it come to the speed of loads in my experience is never very accurate. FS

 

[stubblejumper]

do you guys think that 200 fps difference is possible from a different barrel?

Different barrel, different rate of twist, quite possibly different chamber dimensions. That difference in velocity is the reason that I don't rely solely on chronograph readings to estimate chamber pressure.

 

[maynard]

Different bore and groove diameters= higher pressures=higher veloicity?
Custom hand lapped Vs. mass produced military barrel?
Different primers, different lot of powder?
Are they using the same 140 gr bullet or just the same weight?
I can see where this could add up to a 200 fps difference.

 

[Ganderite]

I have a pair of 308 target rifles made with 2 high quality barrels that were made on the same day with the same tooling. Installed on actions with consecutive serial numbers by the same gunsmith using the same chamber reamer. 150 fps difference with same ammo.

Go figure.....

 

[bearhunter]

Nosler reloading guide shows.
23'' lilja barrel 1-9'' twist
46.5 gr of RL22
2740fps
...........................................................
Lyman reloading guide shows.
Swedish Mauser m38 24'' barrel
1-7.5'' twist
47 grs of RL22
2576fps.
.............................................................
both bullets are 140 grs
do you guys think that 200 fps difference is possible from a different barrel?

Different barrels will give different velocitied with the same load quite frequently, as Ganderite mentioned about his.

In your case, IMHO it has more to do with the twist rates. My bench rest rifles, in 30 cal, with 1-14 twist rates, always gave higher velocities than the same bullet being fired out of a hunting rifle whose chamber was cut with the same reamer.

Even kept the neck and throat the same, until I got tired of turning down the necks to fit.

The difference was the twist rate, 1-10.

I was trying to shoot 130 grain R Robinette bullets out of both rifles and had some home swaged 130 grain bullets made up with heavier jackets and hollow points.

The 1-10 twist bbl was always a couple of hundred fps slower. Very accurate, just slower.

 

[Rory McCanuck]

I have a pair of 308 target rifles made with 2 high quality barrels that were made on the same day with the same tooling. Installed on actions with consecutive serial numbers by the same gunsmith using the same chamber reamer. 150 fps difference with same ammo.

Go figure.....

Had similar results with cars when working at a car rental company.
Same colours, options, everything, and consecutive serial numbers.
One was a lemon, the other, unstoppable.
Weird.