I have heard from several sources that there's supposedly different 7 mm standards for Europe and US?

Supposedly US bullets are 7.21 mm and European bullets 7.24 mm in diametre. The land diam. is supposedly 7.0 mm for US and 6.98 mm for Europe??

Can enyone "out there" enlighten me on this ...
I find it very interesting to know if there's a difference, and I am shure many others also would like to know.

I'm following this post with great interest, to see if it is a difference.

Yours

- Doesn't the CIP - standards state these differences ...
- Is there any experiences concerning accuracy, loading, pressures ... ?

Correct but of no practical importance. My 7x64 shoots .284 American bullets into < .75 MOA.

I'm with Andre, except I'm not so sure whether the difference in 7mm specs makes a difference or not?? I have a European 7x65R, and thus far it has refused to shoot anything but CIP 7mm spec bullets. But, naturally I have to admit that I don't strictly *know* whether this is due to the difference in bullet diameters.

Nomally, it is considered fine to shoot 7mm bullets made to US standards (SAAMI - I take it??) in rifles with CIP spec bores. The other way around, you *might* encounter high pressures.

I actually find it somewhat confusing and worrisome, that 2 different standards exist - it seems a rather appalling idea!
- mike

I have a Dakota Model 10 in 7mm Dakota. Supposedly they Use Lothar Walter barrels (Euro Spec?). This rifle appears to have a very tight bore. I get maximum listed velocities using several grains less powder shown in either the Hornady or Barnes reloading data.
Maybe this is a result of this difference. I'll research it further.....Dj

I sent an e-mail to GS - Custom Bullets < !--color--> of South Africa conserning this issue. They make as standard two different 7 mm bullet dimensions. Here's the answer I got (Their service, as their bullets, are OUTSTANDING!).

Their reply (my name is Aril):



Hello Aril,

There are more than two standards and it is quite amazing that rifles sometimes shoot as well as they do with the bullets that are used. It is also clear that the reason for the bad performance of some 7mm rifles can be found in mismatches of barrel and bullet. We have found that when European manufacturers make rifles, they conform to the CIP standards below. The Americans tend to use only the 7mm Rem Mag dimensions for everything.



The 7x61 Super was developed by Sharpe and Hart in the USA and every one I have seen was built by Schultz and Larsen to the specification below. Given that most bullets available are 7.214, that explains why the 7x61 has such a good reputation.



Similarly, the "oversize" bore and groove dimensions of the 275 HV Rigby will allow somewhat higher speeds than a 7x57 with 7.24 bullets. Accuracy with 7.214 bullets is usually not good.



With our HV Bullets we make two sizes to accommodate the two larger groups. Should a customer have a 7x61 and ask us for it, we run him a batch of 7x57 bullets 20 micron under size. If requested, we run 7x57 bullets at 10 micron oversize for 275 Rigby.





Calibre ---------------Bore---Groove-Twist

7mm Wea Mag - 7.020 - 7.210 - 254

7mm Rem Mag - 7.040 - 7.210 -241

7-08 ----------------- 7.040 - 7.210 - 241

280 Rem ---------- 7.040 - 7.210 - 254

7x61 Super ------- 7.000 - 7.220 - 229

7x64 ----------------- 6.980 - 7.240 - 220

7x57 ----------------- 6.980 - 7.240 - 220

275 HV Rigby ---- 6.970 - 7.250 - 203



If I can help with anything else, just let me know.



Regards

Gerard