7MM BenchRest

[crustyrusty]

If you are going to shoot lapua brass, then go CIP spec, it would be a mistake to do otherwise.

what is the difference between the two? I only know of SAMMI

 

[crustyrusty]

what is the difference between the two? I only know of SAMMI

because I have lapua brass, converted 280 remington brass, converted 6.5 creedmoor brass, 7mm BR brass and converted 300 savage brass

 

[Laurie]

what is the difference between the two? I only know of SAMMI

The C.I.P. is the European equivalent of SAAMI, but has greater powers in signatory countries as firearms proof testing to CIP standards is a legal requirement before sale in Europe, whereas there is no such legal requirement in the USA.

https://en.wikipedia.org/wiki/Commi...nte_pour_l'Epreuve_des_Armes_à_Feu_Portatives

SAAMI and CIP work closely together so that there is rarely a mismatch between their specifications. Just as SAAMI produces specs and drawings for cartridges that originate in the US, so CIP has this function for European designs, eg 6.5X47mm Lapua.

The BR series is unusual in that they were originally US (Remington) designs, but Norma of Sweden (a CIP signatory) picked up the design with a modernisation of the 6mm BR for heavier / longer bullets in 1996 as the 6mm Norma BR and Norma and Lapua started production of brass and cartridges. Although the main changes are to the rifling twist and freebore it seems the back end of the chamber was also slightly enlarged and Lapua BR brass has a slightly 'fatter' lower case-body than its Remington equivalent. Today's 6mm BR chamber reamers and variants that use 6mm Norma BR Lapua brass necked up or down are dimensioned to suit. If an original SAAMI / Remington spec reamer is used, this case will likely be marginally tight in the chamber giving a degree of hard chambering and a lot of difficulty in extraction. (Been there with 6BR and got that teeshirt!) You end up having to get the chamber honed out fractionally or using a 'small-base' body sizer die.

When people say to insist on the CIP spec reamer, there won't be such a thing as AFAIK the CIP has never adopted the 7mm variant, it being an obsolete design so far as the firearms and ammunition manufacturing industries are concerned and has never been produced within Europe. There will therefore not be any CIP specification in existence. What they really mean is that if you intend to use Lapua 6BR brass necked up, to ensure the reamer manufacturer knows that and specs the reamer to suit that case's lower dimensions.

 

[crustyrusty]

ok good to know I have commissioned Dave Manson Precision to make my reamers ( 3 of them to be exact !!!! 7MMBR,, 6.5X55,, & 280 British) so that makes 2 reamers to be made CIP standards, actually
come to think about it all three will be CIP with one for sure CIP Match...

 

[crustyrusty]

Hello I am in need of advice.. I am in the procces of having a reamer being made for the 7MM BR and the company I am using has a build sheet to spec the reamer to. what I dont understand is what does C.I.P. mean and can I increase the neck diameter from normal spec of .309-.310 to a more user friendly .312? I found out that there are no SAAMI specs for this case just CIP.. I dont mind having to neck turn cases but if I can make it easier that is good for me. but when I was looking at the reloading dies all were based on the tight neck so does that mean I would have to have a set of custom made dies to match my new reamer specs?

I now have the reamer and the rifle is in the smiths shop!!! thank you for all your help and advice!!