30-06 Autofrettage & Proof electric & percussion primed extractorless


#1

The grey ring between the center tin plated copper disk and the outer ring raised metal is like a grey epoxy or plastic. Not ceramic or lead. Must be an insulator which leads me to believe they may be electric primed. Why do I feel the center disc is tin plated copper, because I can see a bit of copper under the tin plating and all is non magnetic.
Silver tip is 421 grains.
FMJ GMCS is 391 grains.

Joe


#2

Joe,

FWIW, here is a diagram of a typical electric primer. Certainly bares some resemblance to the primes shown in the photos above.

(Diagram from Investigation of Metastable Interstitial Composite (MIC) Materials for Electrically Initiated Lead Free Primers, 2004. DTIC #A480874)

Brian


#3

Hi Joe
Yes definitely electric primed. Not seen the FMJ variation with that primer, so quite interesting.
Another FMJ variation has a typical ring-crimped domed brass, a GM-jacketed bullet & is headstamped F A TEST (with serifs).


#4

These Autofrettage are obviously a limited usage round, as you see much more prevalent the standard cartridge dimension proof rounds out there, military or commercial. I suppose you could argue it was two different usage concepts.

Pete, your F A TEST Autofrettage, (correction, proof, not Autofrettage) does it have the same 2 tics 120* apart (correction, 90° apart) as mine at the base? Mine is also a GM projectile. Weight is 425.5 grains.

Joe


#5

Hi Joe
ticks are more like 90º apart & weight is 421.8gr.


#6

Pete,
Yes, correct. On reexamination I concur, more like 90° apart. On the Silver Tip they are 180° apart.

After being contacted by three other collectors about my post, I have formed more of a theory that the smooth no rim or extractor grove 30-06 chamber dimension rounds I posted are more likely just proof rounds. I post another possible electric primed proof below with what looks to me like a Remington style projectile. The next post below, I will post what I theorize to be a true Autofrettage round for forging a unfinished, bored barrel blank from the inside out.
Weight 458 grains.

Joe


#7

Possibly a true Autofrettage round for forging a unfinished, bored barrel blank from the inside out.
Case length: 2.540" or 64.52mm
Rim: 0.440" or 11.19mm
Base: 0.438" or 11.14mm
Shoulder: 0.399" or 10.15mm
Neck: 0.316" or 8.04mm
Lead projectile diameter outside neck: 0.292" or 7.44mm
Lead projectile length from mouth: 1.069" or 27.15mm
Weight 438 grains.


#8

Being one of the three, here is a picture I shared with Joe.

left to right
first two: no headstamp, weight 402 grain, 445 grain
two similar rounds with H/S: FA TEST, weight 430 grain, both also have the Tics
on the right, H/S : WRA CO 27, weight 430 grain


#9

Rene,

Dimensions on M1515 please when you can.

Joe


#10

Joe,

I would say, identical to yours
OAL 91,7 MM
case 64,55 MM
base 11,2 MM
shoulder 10,2 MM
casemouth 8,14 MM
Bullet 7,48 MM

variances due to measurements “Errors”

cheers
René