"Slow barrels".

[JeffinNZ]

Team.

My Lee Enfield No.4 MkII shoots cast bullet (and the other sort for that matter) like a house on fire. Honestly I never thought a LE and cast could do 1.5-2.0 MOA consistantly but she's proved me wrong.

Thing is though, the MkII has a "slow barrel". When working on top end loads I can never get even close to the listed velocities.

For example: if a manual lists 2700fps for 'X' load I might get 2400fps.

Now I know about variation in data and rifles but we are talking 15% here which is a lot.

Has anyone else experiences a 'slow' or for that matter 'fast' barrel?

[Bret4207]

You may want to check and see if your chamber is oversize. That would allow for less pressure/velocity. On my #4 I can up the charge a bit due to a fat chamber. I neck size the fire formed brass and you can really tell the difference from factory just by a glance at 2 cases laying side by side.

[JeffinNZ]

Good thinking Tpr. Bret.

I had speculated such and I know that the No.4 has got a large chamber. I have to anneal my cases necks regularly even though I only use a Lee collet die as they expand so much.

I once tried neck expanding to 8mm to create a secondary shoulder for headspacing new cases and even at 8mm the cases STILL chambered.

[Bret4207]

SOunds generous. You're on the right track I think.

[Frank46]

Jeff, only thing that comes to mide regarding "slow bbls" is an srticle I read some time back about tests being done with the 270 winchester cartridge. The writer had made mention about some of the bbls were either fast or slow. Other than that I think you are on the right tack as the bigger the chamber is the more room for gas expansion. Ever tried putting a 223 case down inside a 303 case to decrease the available case capacity and using reduced charges. There was I believe an article in either handloader or rifle magazing where one writer di just that on one cartricge he was working on. Frank

[Ricochet]

How in the heck could you get a .223 case inside a .303 case?

[Frank46]

I believe the writer had opened up the neck and altered the 223 case to fit inside the case he was using and then resized the neck to the caliber he was using.
This was done to reduce the internal case volume and allow smaller charges of powder to be used. Frank

[Bret4207]

The article appears in Wolfes "The Art of Casting Bullets" which IF you can find a copy usualy goes for $50.00+. The 223 case was lathe turned to fit inside a 308 case, which was opened to a straight taper. After the reduced 223 case was inserted the 308 was reformed to specs, then fire formed. IMHO it would have been cheaper and easier to have 20 308 cases lathe turned from brass with a reduced internal capacity. Or for that matter, just fill the bottom half of the 308/30-06/300 Win Mag/whatever with hot lead, drill the flash hole out (you'd have to experiment a bit to get good ignition) and away you go!

[Frank46]

Tpr.Bret, thanks for posting the source of the 223 case usage. $50.00 for the copy. I have all three. Still a bit of good reading every now and then. Guess if you hold on to something long enough it will be worth something. Frank

[matm0702]

I measured some loads fired from my M44 carbine which I thought were a little slow compared to what was posted in my load data. They were starting loads using a 150 grain .312 hornady bullet that were rated at 2700+ FPS but chronied at 2500. I knew I would lose a little velocity with a carbine (20 in) length barrel but didn't expect this much of a loss. Unfortunately the chrony died before I could test loads in a M39 with a 27 inch barrel to check for higher velocity. The loads tested did group well so overall the velocity matters little as the loads tested are more than enough to take care of bambi.

Mike