7mm RM Fed 215 vs CCI 250 primers- pressure problems

[Shootin4fun]

Hi Guys,

I'm trying to figure out what's causing the primer pockets on my 7RM to expand after only 2 firings such that the primers start showing gas leaks and falling out after firing.

That I know, is a potential sign of a pressure problem I changed from Fed 215 to CCI 250 mag primers.

IMR4831 (all from same bottle), 140gr TTSX - I dropped the charge from 62.9 with Federal 215s where there were no problems before to 62.3 with CCI 250 where there were 75% a stiff bolt and blown primers to 61.0 of where 1 of 3 blew it's primer. 59.5 didn't blow any.

Has anyone seen such dramatic differences by changing from Fed to CCIs? Actually, I'm not sure if it's the primers doing it or something else. But something has changed over time to cause this.

Interestingly, during this period Barnes lowered their max loads from 63.0 to 59.5 in 3 steps.

 

[DocDoc]

Primer pockets expanding, primer leaks, and primers falling out - too much pressure. An example of why you should drop the powder load and work back up when you change any component.

 

[Shootin4fun]

Okay, I'll buy that. I'm surprised that as much as 5% is required from a primer brand change.

Next I will ask, would new brass that is .019 shorter in headspace than other brass from the same lot due to not being fired yet be expected to cause a noticeable pressure increase?

 

[Gord0]

Where are you measuring the headspace from? If from the shoulder then .019" would definitely increase pressure.

 

[Shootin4fun]

Yes from the shoulder to the headstamp. I understand of course that the reduced cabin space increases pressure but am not sure if .019 would be that significant. I would like to fireform them but the rifle and reloading setup are a half continent apart! :-( Don't ask.

So it looks like I'll be buying some off the shelf ammo and blasting that away to get some fireformed brass. Which is okay because now that I put a brake on this thing, it recoils like a 243 and I can do 30+ in a day. It is (or was) capable of very tight groups.

 

[Barrelnut]

How far are the TTSX bullets from the lands? Barns bullets require a good jump. Copper TTSX bullets cause higher pressure than copper lead core bullets and require a longer jump to reduce pressures. If you have them seated right at the lands, that might be a problem.

I've changed between F215M and CCI 250 before. My experience is the F215Ms are a little stronger. I was getting 10 ~ 15 FPS faster speeds with the F215M. Could have a lot to do with the lots of primers I have too... But haven't seen those types of pressure issues switching between them.

 

[Lefty7mmstw]

Hi Guys,

I'm trying to figure out what's causing the primer pockets on my 7RM to expand after only 2 firings such that the primers start showing gas leaks and falling out after firing.

That I know, is a potential sign of a pressure problem I changed from Fed 215 to CCI 250 mag primers.

IMR4831 (all from same bottle), 140gr TTSX - I dropped the charge from 62.9 with Federal 215s where there were no problems before to 62.3 with CCI 250 where there were 75% a stiff bolt and blown primers to 61.0 of where 1 of 3 blew it's primer. 59.5 didn't blow any.

Has anyone seen such dramatic differences by changing from Fed to CCIs? Actually, I'm not sure if it's the primers doing it or something else. But something has changed over time to cause this.

Interestingly, during this period Barnes lowered their max loads from 63.0 to 59.5 in 3 steps.

am I reading this right?? you dropped only 1/2 grain on a component switch when you were at top load???

As to the load data getting more conservative, there are a lot of differences in 7rem data between sources and time they were released... There is a reason they are stopping where they did-- they hit max. safe pressure in that particular combination using that rifle.

 

[Shootin4fun]

I have had good luck with the OAL Barnes suggests. Here's the saga with Barnes powder charges. My COALs are as follows:

TTSX COAL 3.230" which = 2.750" Ogive as measured with Hornady compator
Ogive to lands = 2.864 Measured with same comparitor

So I am .114 off the lands. Yes, that's seemingly a lot.

The measurements are the same with the 120 TTSX because it has the exact same profile.

All load data from Barnes. When I started out, the TTSX wasn't even listed yet so it was 140 TSX seated to .136" off lands using their COAL.
Max was 63.0gr IMR 4831. Accurate load, 3200 - 3240 fps. No pressure problems.

Then one day TTSX was listed in the next set of charts and they dropped it to 61.2 for both TSX and TTSX, and I kind of freaked thinking my notes were wrong but found the previous chart I had printed out so called them; they confirmed. (Hinted new engineers, maybe legal concerns.)

Then another set came out and max was 59.6 where it stands today.

I find that 60.0 blew no primers but 1 leaked however could have been a loose pocket to begin with. Low number of samples.

59.5 is okay, no blown, no leaks but low number of samples.

Unfortunately none of these have been as accurate as the old 62.9 load with 140 TSX & Fed 215 which showed no pressure signs but I will make up more at 59.5 and go from there. That's why I started this tread asking if anyone experienced similar result with Fed vs. CCI. Haven't been able to find Fed 215s anywhere for a long time.

As I think most will agree, Barnes like to be pushed to near max for best accuracy which is what I'm aiming for. My velocities are higher than Barnes listed for given charges on both 140 &120 TTSX.

In fact 120 TTSX, is going 3395 with 64.5 IMR4831.
Barnes lists 3328 with max load of 68.9, do 67fps slower with 4.4gr MORE powder. 64.5 is accurate, .5"x .2" vertical 5 shot groups if I do my part.

Thanks for your feedback.

 

[turkeyfever]

I had this happen with H1000 shooting 7mm rem mag and 168 grain bergers. I had to drop charge 1.2 grains to get velocity back to what it was before. A half inch rifle was now shooting 1 1/4 to 1 1/2 groups. Brought another jug of H1000 and things are good to go.

 

[Lefty7mmstw]

I have had good luck with the OAL Barnes suggests. Here's the saga with Barnes powder charges. My COALs are as follows:

TTSX COAL 3.230" which = 2.750" Ogive as measured with Hornady compator
Ogive to lands = 2.864 Measured with same comparitor

So I am .114 off the lands. Yes, that's seemingly a lot.

The measurements are the same with the 120 TTSX because it has the exact same profile.

All load data from Barnes. When I started out, the TTSX wasn't even listed yet so it was 140 TSX seated to .136" off lands using their COAL.
Max was 63.0gr IMR 4831. Accurate load, 3200 - 3240 fps. No pressure problems.

Then one day TTSX was listed in the next set of charts and they dropped it to 61.2 for both TSX and TTSX, and I kind of freaked thinking my notes were wrong but found the previous chart I had printed out so called them; they confirmed. (Hinted new engineers, maybe legal concerns.)

Then another set came out and max was 59.6 where it stands today.

I find that 60.0 blew no primers but 1 leaked however could have been a loose pocket to begin with. Low number of samples.

59.5 is okay, no blown, no leaks but low number of samples.

Unfortunately none of these have been as accurate as the old 62.9 load with 140 TSX & Fed 215 which showed no pressure signs but I will make up more at 59.5 and go from there. That's why I started this tread asking if anyone experienced similar result with Fed vs. CCI. Haven't been able to find Fed 215s anywhere for a long time.

As I think most will agree, Barnes like to be pushed to near max for best accuracy which is what I'm aiming for. My velocities are higher than Barnes listed for given charges on both 140 &120 TTSX.

In fact 120 TTSX, is going 3395 with 64.5 IMR4831.
Barnes lists 3328 with max load of 68.9, do 67fps slower with 4.4gr MORE powder. 64.5 is accurate, .5"x .2" vertical 5 shot groups if I do my part.

Thanks for your feedback.

I suggest you switch powder... I have had very good luck using rl22 in my old 7rems (3 of them) with 140's... I am currently running rl25 in my 7stw with 140ab's... The slower imr powders have been issues for me with the 7rem and stw too, but more so with 7828...

 

[KurtB]

I don't think I would say that a .5 grain drop and fewer/no blown primers = safe pressures.

 

[Shootin4fun]

I don't think I would say that a .5 grain drop and fewer/no blown primers = safe pressures.

It is not just a .5 grain drop from the beginning of this saga to the end. It went from 62.9 to 59.5. That's why I asked about opinions on the potential effect of changing only the primer brand. It seems like a big leap to get back to safe pressures.

 

[Dosh]

4fun, several relatives and friends load for 7RM, some use 215M and some use Remington 9 1/2M. All with the same bullet and powder with little difference in powder charge. Have you tried a new batch/ brand of brass. There are some brass that has been commented on lately as having loose primers after only the second firing. Quality brass of the same lot may be a consideration. Good luck

 

[243winxb]

HIGH PRESSURE -Primer pockets may expand a little at each firing. May take 2 or 5 firings, but the primer will fall out or gas will leak soon or later.