CIP or Saami gauges.

[mas36]

Hi guys I have just discovered your forum. I live in the UK. I have been shooting and re loading for over 30 years.
I have been reading some of the posts with interest especially the gun Smith stuff. I have a shop out back of my house with a couple of lathes a Mill etc.
Its really difficult in the UK for an ordinary shooter to do any kind of barrel work or any thing to do with fettling guns. Every thing in the UK has to be licenced. You can not buy a barrel blank or go no/go gauges or reamers unless you are a registered gunsmith.
Any way I have a question.
Is there a difference between a saami reamer and CIP reamer.
If you had for example a Saami .308 reamer and a set of go no/go CIP gauges could you still cut the chamber.
Or if your reamer is saami do you need saami go no/go.

 

[rwj]

It’s my understanding that there are not duplicate SAAMI and CIP standards for the same chambering/caliber...

 

[Ray Gross]

It is a mixed bag. Some calibers will have the exact same headspace for both SAAMI and CIP. Others may be .002-.003 different, sometimes more. There are often slight shoulder angle differences as well.

My suspicion is that many of the differences are caused by the conversion back-and-forth from metric to inch and vice versa and the fact that the two organizations notate their prints differently.

For example, CIP does not have a separate headspace length or headspace datum diameter. Instead you have to calculate it using the L1 and L2 lengths, the P2 (shoulder) and H1 neck/shoulder junction diameters, the shoulder angle and some trigonometry. Also note that CIP denotes the shoulder as an 'included angle' while SAAMI uses the angle per side.

For 308 Win, you are safe to mix and match. The head space and shoulder angle is exactly the same for both standards. There are slight differences between the chamber dimensions, but functionally they're interchangeable.

 

[rwj]

Learning that the same chambers are specified by different standard organizations is surprising and sounds like a recipe for problems!

 

[JASmith]

I discovered a difference between the SAAMI and CIP specifications for a cartridge I follow a few years back. What I learned was that the two organizations do work to harmonize the specs so the resulting cartridges and chambers match.

The difference I found was corrected after about a year. It takes that long for the very detailed coordination and verification process to go through.

I am also very sure that not all cartridges with the same name are harmonized as much as we would like. but I know the effort is made.

Another important difference isnthat compliance with SAAMI standards is voluntary while CIP standards are mandatory. In practice, however, most American manufactures carefully adhere to the SAAMI standards. One can guess that liability issues are more easily handled if the audit trail shows the company followed an accepted standard.

 

[Laurie]

You can not buy a barrel blank or go no/go gauges or reamers unless you are a registered gunsmith.

Not so. Blanks are free purchase as are gauges and chamber reamers. As soon as you cut a chamber though, the blank becomes a 'firearm pressure bearing component' and is licensable.

 

[Laurie]

I am also very sure that not all cartridges with the same name are harmonized as much as we would like. but I know the effort is made.

One area where there is frequent (and happy) non-harmonisation is maximum allowed pressures. Many European former military cartridges have considerably higher CIP MAPs than US SAAMI values. Notable examples include 6.5X55 ('SE' version), 7 and 8mm Mauser. (The UK and EU legal requirements for previous valid proof testing before sale probably ensures that unsafe 'clunkers' are taken out of circulation.)

It also applies to some modern cartridges, especially those associated with the AR-15 platform including 223 Rem, 6.5 Grendel and no doubt 6-ARC Hornady if and when it gets onto CIP.

 

[mas36]

Not so. Blanks are free purchase as are gauges and chamber reamers. As soon as you cut a chamber though, the blank becomes a 'firearm pressure bearing component' andI

 

[mas36]

In theory yes but I have never found any reamer maker go no/go gauge maker or barrel blank manufacturer that would sell me any of there products in the UK unless I was a registered fire arms dealer. I am in the market for a set of go no/go gauges in 7.62x54R if you know were I can purchase a set in the UK I will be grateful.