Re: Whay do \"Palma\" barrels have tighter bores? Speed , accuracy?
Krieger's explanation is somewhat vague, so hopefully i will be able to fill in the gaps. Formal Target rifle shot under British NRA rules developed from Service rifle in the late 1940s and thus used service ammunition, so when the 7.62 NATO was adopted in the 50s, so was the round for Target rifle, where it remains today. All competitions are shot with ammunition issued by the NRA, which is usually 7.62 Nato Radway Green sniper grade, hence the smaller bore and groove diameter. The international Palma match is developement of Target rifle and thus uses the some of the same rules.
Its good to see that your NRA has seen the light and allowed their competitors to use their own ammunition and not be saddled with sub-standard military crap.
Some years ago the Queens meeting at Bisley was at risk because of the dire quality of the "MOD" procured "non domestic" sniper grade ammo, some of which did not go off, others jammed and accuracy was abismal and this is the stuff they give our armed forces! Anyway, strings were pulled and a batch of RG sniper grade ammo was sourced and the meeting saved!
Here in England we do not have a domestic ammunition industry and procurement is from countries to whom we once supplied ammunition.