chronoed my whelen

[jhalcott]

  I chrono graphed my 35 Whelen load that uses 44/Varget and a flat nosed 358318. I got 1995fps,pretty close to what I wanted (2000/2100 fps). I ran some teflon taped 280468 bullets in 7tc/u cases and got 1870 fps thru a 14" and 2039 from a 21". The same bullet with Felix lube hit 2093 (14") and 2247 (21"). The RCBS 180 FN 30 cal managed 1793 from a 14" barrel using 27/3031. Another 30-30load using the 311291 bullet and 8.8/PB averaged 1256 from that barrel. I had some trouble chambering some 7tc/u loads in the 21" barrel that fit the14". In the 14" barrel it went 1206fps .The load uses a charge of Unique and a 168 cast gc bullet.

[Black Jaque Janaviac]

5 fps short of the as-advertised velocity... not bad.

Hey, I've wondered if there isn't an advantage with the larger calibers when it comes to paper-patching.  They say soft lead will come apart due to the spin when velocities exceed 2200 fps.  But larger bore rifles tend to have a slower twist.  I crunched some numbers and found that for a given velocity of 2500 fps, the velocity of the perimeter of the bullet can be almost 100 fps slower in a .35 caliber rifle compared to a .30 cal.

Velocity of the circumference of a .358" bullet when fired at 2500 fps through a 1:16" twist rifle = 175 fps.

Velocity of the circumference of a .308" bullet when fired at 2500 fps through a 1:9" twist rifle = 269 fps. 

So what I'm getting at is:  Could you fire a pure-lead bullet through a .35 Whelen at higher velocities than you could fire a pure-lead bullet through a .308 Winchester (or 7mm TCU  or ...)?

[jhalcott]

  are you asking about a "naked " bullet or a lubed or patched one? A paper patched bullet of 40-1 alloy can be shot thru a 45-70 with good accuracy. The paper patch protects the bore from contact with the lead up to surprising velocities.You run into recoil induced problems real quick with big heavy slugs in shoulder/hand held guns.! Internal ballistics is a field in itself.I've read of experiments with pure lead being shot at 3000 fps in special guns that penetrated 1/4" steel at 100 yards..50 caliber projectiles were used.

[Black Jaque Janaviac]

are you asking about a "naked " bullet or a lubed or patched one?

No.  Paper-patched. 

My understanding is that the velocity limitations of the paper-patched bullet are not due to leading the bore (as naked cast bullets do) but due to either spinning apart or atmospheric friction. 

I've read that a paper-patched pure lead bullet can't go much past 2200 fps.  If you push it above that, you need to harden the lead, again not for internal ballistic reasons, but external ballistic reasons.  I thought that perhaps the 2200 fps figure was derived from experience with a .30 caliber weapon.  Typically .30 twists are 1:9" give or take an inch.

So maybe you could drive a pure-lead, paper-patched .35 Whelen to say, 2400 fps, whereas a pure-lead, paper-patched .30-06 would be limited to 2200 fps. 

If the velocity limit is due to atmospheric friction, then caliber won't make a difference, although perhaps B.C. would.  It doesn't appear that the atmospheric friction would be the cause of problems with pure lead projectiles.  Lead exposed copper jacketed bullets can be shot at very high velocities.

Actually, I think Dead Center makes some non-jacketed muzzle loader bullets that are intended to be shot at 2600+fps.