What OAL are you guys using for the Bullet Barn 200gr .303?
For use in my No.4 Mk.2.
I load mine to about 2.95 OAL. Just to the top of the band on the bullet. I guess that depends on whether you have trimmed your cases or not. Anywhere under 3.00 is good.
You can color the bullet nose with a black Sharpie then gently
chamber it and look for scuffs where it may be touching the throat.Seat a little deeper color again ,then check till it's not and fits the magazine.
Your No 4 Mk 2 has probably not suffered the throat erosion that my older rifles have. Load a dummy round long and close the bolt on it. That will tell you your OAL. Theoretically, if it fits in the mag it will chamber in the gun.
What velocity can those take?
I was debating on 174 175 grain vs a 200 grain for a number 1 Mark 3 anyone got advice??
If they aren't gas checked, the heavier bullet allows you to get some more pressure for a better powder burn while still staying at lower velocities in the 1500 fps range.
If it's gas checked you can push them faster and get the pressure up. Can get close to 2000fps using 4198 or or similar powder.
Have you checked your bore? Some of the MKI have oversize bores and chambers. I have a No1 MKIII that needs a .314" or larger cast bullet to stop key-holing at 50 yds.
I was debating on 174 175 grain vs a 200 grain for a number 1 Mark 3 anyone got advice??
I checked the .310 Hornady ones I have here and both my mark 1 and no4 that's sporterized are tight, so it's good, I throat checked by putting a bullet into the end, and it never went in the muzzle too far, maybe 4 or 5 mm, I shot ppu 174 grains and some Winchester 180 grain pp, and perfect
I was shooting 200 gr cast Bullet Barn bullets with 38 grns of 4895. Accuracy wasn't great at 100 yards but I did manage a 3" group. Ladder test with 4895, 36 grns to 40. I intend to do some more research as I only got to shoot that load in one #4 rifle. I want to see how it does in an old No. 1.
H 4350 is my choice for full velocity cast boolit loads in the .303 British.



























