Thread: 257R Experiences

loaded up using R-P new brass, numerous misfires with poor primer strike, no problem with Norma ex 7x57 cases, checking brass the R-P has a much wider extractor groove, remember many moons ago having or hearing about a similar problem with 257 brass but can't remember exactly.

Originally Posted by tetawa

loaded up using R-P new brass, numerous misfires with poor primer strike, no problem with Norma ex 7x57 cases, checking brass the R-P has a much wider extractor groove, remember many moons ago having or hearing about a similar problem with 257 brass but can't remember exactly.

in theory, because it headspaces off the shoulder..the size of extractor groove SHOULDNT come into play at all....be interesting to find out what is going on.

Originally Posted by tetawa

loaded up using R-P new brass, numerous misfires with poor primer strike, no problem with Norma ex 7x57 cases, checking brass the R-P has a much wider extractor groove, remember many moons ago having or hearing about a similar problem with 257 brass but can't remember exactly.

Did you seat well out to get bullet jam for fireforming? This really helps eliminate light strike issue.

Sent from my SM-S906E using Tapatalk

Originally Posted by Mathias

Did you seat well out to get bullet jam for fireforming? This really helps eliminate light strike issue.

Sent from my SM-S906E using Tapatalk

Yes, 117 RN way out to get jam. Barely marking the cases, with ex Norma 7x57 great strike. same primers. Have primed and fired both with m't brass, no problems with the ex 7x57. Will put up photo tomorrow showing the difference in extractor grooves.

Originally Posted by tetawa

Yes, 117 RN way out to get jam. Barely marking the cases, with ex Norma 7x57 great strike. same primers. Have primed and fired both with m't brass, no problems with the ex 7x57. Will put up photo tomorrow showing the difference in extractor grooves.

I had a similar problem with my 260 improved and found if I gently closed the action on the round rather than normal speed, I had a higher success rate. Shutting too fast pushed the projectile into case & I got less headspace jam & a weak strike


Sent from my SM-S906E using Tapatalk

Originally Posted by tetawa

loaded up using R-P new brass, numerous misfires with poor primer strike, no problem with Norma ex 7x57 cases, checking brass the R-P has a much wider extractor groove, remember many moons ago having or hearing about a similar problem with 257 brass but can't remember exactly.

Greetings @tetawa,
The problem was likely that the R-P brass was shorter to the shoulder than Norma. The yanks, being what they are came up with a different chamber than the Mauser standard in the days before SAAMI. so SAAMI dimension cases will be short in the Mauser chamber, Having done this the US rifle manufacturers had to cut the chambers long enough to accept the continental round. This was well covered in a recent rifle or handloader and from my experience happened with the the 6.5x55 and likely others as well. Get yourself a headspace comparator tool from Hornady and do some measuring.
GPM.