I apologize in advance if this question is somewhat obvious to you experienced folks out there 
I just came across a site that was selling Lapua 7.62x53R brass. They seem to imply that it is also 7.62x54R brass. (http://www.targetshootingproducts.c...d=526&osCsid=9594cc483b61ab34b16a69ab32969338)
Now I understand that 7.62x53R can be used in the Russian guns with a slight loss of accuracy.
However, I can't see them selling this stuff as the same if the user would suffer a loss of accuracy using the slightly smaller cartridge in the larger gun. Is the brass considered completely interchangable, with the main difference being a slightly smaller bullet in the 7.62x53R?
Here are the relevant details on the two cartridges - note that there are some small differences in the case sizes, as well as a difference in bullet size. Do the small differences in case dimensions make a difference?
Or is the site above out of line selling the brass as being proper for both weapons when in fact using it in a 7.62x54R weapon would result in a loss of accuracy?
7.62x53R
Bullet diameter 7.83 mm (0.308 in)
Neck diameter 8.55 mm (0.337 in)
Shoulder diameter 11.61 mm (0.457 in)
Base diameter 12.42 mm (0.489 in)
Rim diameter 14.40 mm (0.567 in)
Rim thickness 1.60 mm (0.063 in)
Case length 53.50 mm (2.106 in)
Overall length 77.00 mm (3.031 in)
Case capacity 4.16 cm³ (64 gr H2O)
Rifling twist 300 mm (1 in 11.81 in)
Primer type Berdan
Maximum pressure 390 MPa (57,000 psi)
7.62x54R
Bullet diameter 7.92 mm (0.312 in)
Neck diameter 8.53 mm (0.336 in)
Shoulder diameter 11.61 mm (0.457 in)
Base diameter 12.37 mm (0.487 in)
Rim diameter 14.40 mm (0.567 in)
Rim thickness 1.6 mm (0.063 in)
Case length 53.72 mm (2.115 in)
Overall length 77.16 mm (3.038 in)
Case capacity 4.16 cm³ (64 gr H2O)
Rifling twist 240 mm (1 in 9.45 in)
Primer type Berdan or Boxer Large Rifle
Maximum pressure 390 MPa (57,000 psi)
I just came across a site that was selling Lapua 7.62x53R brass. They seem to imply that it is also 7.62x54R brass. (http://www.targetshootingproducts.c...d=526&osCsid=9594cc483b61ab34b16a69ab32969338)
Now I understand that 7.62x53R can be used in the Russian guns with a slight loss of accuracy.
However, I can't see them selling this stuff as the same if the user would suffer a loss of accuracy using the slightly smaller cartridge in the larger gun. Is the brass considered completely interchangable, with the main difference being a slightly smaller bullet in the 7.62x53R?
Here are the relevant details on the two cartridges - note that there are some small differences in the case sizes, as well as a difference in bullet size. Do the small differences in case dimensions make a difference?
Or is the site above out of line selling the brass as being proper for both weapons when in fact using it in a 7.62x54R weapon would result in a loss of accuracy?
7.62x53R
Bullet diameter 7.83 mm (0.308 in)
Neck diameter 8.55 mm (0.337 in)
Shoulder diameter 11.61 mm (0.457 in)
Base diameter 12.42 mm (0.489 in)
Rim diameter 14.40 mm (0.567 in)
Rim thickness 1.60 mm (0.063 in)
Case length 53.50 mm (2.106 in)
Overall length 77.00 mm (3.031 in)
Case capacity 4.16 cm³ (64 gr H2O)
Rifling twist 300 mm (1 in 11.81 in)
Primer type Berdan
Maximum pressure 390 MPa (57,000 psi)
7.62x54R
Bullet diameter 7.92 mm (0.312 in)
Neck diameter 8.53 mm (0.336 in)
Shoulder diameter 11.61 mm (0.457 in)
Base diameter 12.37 mm (0.487 in)
Rim diameter 14.40 mm (0.567 in)
Rim thickness 1.6 mm (0.063 in)
Case length 53.72 mm (2.115 in)
Overall length 77.16 mm (3.038 in)
Case capacity 4.16 cm³ (64 gr H2O)
Rifling twist 240 mm (1 in 9.45 in)
Primer type Berdan or Boxer Large Rifle
Maximum pressure 390 MPa (57,000 psi)
