Thread: 7mm Rem Mag Troubles

Righteo. Pls help.

So I've been having a bit of fun/frustration recently reloading for my 7mm Rem Mag Browning X-Bolt. I've been running the 162g ELD-X with AR2217, 20 thou off lands.

First attempt (new brass):

Did a pressure test - one round each charge, increasing half grain each time til quite far over max (up to 74.0g) because wishful thinking. Managed to get up to that point with no sticky bolt - only some faint ejector stamps. Good (and expected) velocities.

Second attempt (once fired brass):

72.5g - light ejector stamp, no heavy bolt lift - average group (just over 1")
73.0g - heavy bolt lift and heavy stamp. Also much higher velocities experienced than in attempt 1. Tried two rounds to make sure it wasn't a rogue load - exactly the same result and the two shots were touching... classic.

Third attempt (twice fired brass):

70.5g - average group, higher than expected velocity - no pressure signs
71.0g - average group, higher than expected velocity - no pressure signs
71.5g - two shots touching and one flier (probably me), roughly expected velocity - no pressure signs
72.0g - three shots 0.5" group, expected velocity - no pressure signs

Fourth attempt (twice fired brass):

71.5g - 2" group, higher than expected velocity - the odd faint ejector stamp
72.0g - heavy bolt lift, heavy stamp, higher than expected velocity
71.5g - heavy bolt lift, heavy stamp, higher than expected velocity (went back to this load just because I was at a bit confused)

There seems to be a pattern here but I haven't worked out what's going on. I'm new to reloading but I also load for my 7mm08 and have found a couple of good loads for that rifle with no issues. I know my rem mag can shoot, as I've had reasonably good loads for it in the past. I have not tried these loads out recently but that would be a sensible next step. I suspect, though, whatever is causing this pressure issue is also causing the grouping to go wonky.

Any advice is very welcome. My suspicions are something to do with cleaning (have heard mention of carbon ring on other threads), possibly funky primers but I'm not sure why that would cause an incremental decrease in pressure threshold, or something completely new to me.

Cheers,
Elliott

I'm not sure what is going on, however I load the 162gr with AR2225 up to 73gr for around 3050fps. In my opinion anything over 70gr of AR2217 is overloaded if you are getting ejector smudges or can see brass flow you are way over pressure. I hope its not a Tikka you will be hammering the bolt lugs into the action keep that up and it will be stuffed in no time. You have to stop chasing velocity and be sensible. Maybe try AR2225.

Tempeture is the problem. When you get to or exceed max load data tempeture of the air, chamber, barrel etc will have a direct impact on pressure i.e. high pressure + temp = higher pressure. Max load data is set for various powders within certain temp values to produce 'x' pressures. Running extra pressure causes some powders to become tempeture sensitive and can become faster burning or explosive.

Originally Posted by Dermastor

I'm not sure what is going on, however I load the 162gr with AR2225 up to 73gr for around 3050fps. In my opinion anything over 70gr of AR2217 is overloaded if you are getting ejector smudges or can see brass flow you are way over pressure. I hope its not a Tikka you will be hammering the bolt lugs into the action keep that up and it will be stuffed in no time. You have to stop chasing velocity and be sensible. Maybe try AR2225.

Yep, fair call. To be clear, I've only put three rounds through that have had heavy bolt - I'm not doing it over and over again.

My confusion is why each time I drop down, I seem to have one load that's sweet and the next half grain up I have signs of pressure. Seems to be incrementally decreasing the threshold even though I'm dropping down each time. At this point I'm worried something is going on with the rifle, as there were zero signs of pressure with these exact loads when I started this development.
@Walker I thought that too. But Saturday was the coldest day I've done this and got pressure on the lowest load so far.

I think the plan is basically to drop right down and start again. But if this could be something to do with the rifle, rather than the loads, I'd like to know so it doesn't keep getting worse.

I went through a similar experience when I started loading that combo in my rem mag, thought I was losing the plot.

How do you set up your scales? I have found that my scales can read a little different depending on God knows what haha but I now use a set of calibration weights every time I load. I think it has helped but who knows haha if you used something like that it could rule out scale variations at least.

After changing my process and using the weights every time I find my loads are much more consistent. I use Redding number 2 scales.

Didn't someone have trouble with eldx's copper fouling the barrel recently?
I remember a thread bout it

Have you pulled any loads to check powder weight is correct....scales may not be zeroed or off level????

Originally Posted by wsm junkie

Have you pulled any loads to check powder weight is correct....scales may not be zeroed or off level????

Yep, have checked weights - all the loads I've checked have been as they should be.

They're beam scales and I've marked on my bench exactly where to put them, then zero each time before I use them.
@kidmac42 I thought that could be it too. I gave the barrel a clean with hoppes before the most recent attempt.

Originally Posted by Rated M for Magnum

I went through a similar experience when I started loading that combo in my rem mag, thought I was losing the plot.

How do you set up your scales? I have found that my scales can read a little different depending on God knows what haha but I now use a set of calibration weights every time I load. I think it has helped but who knows haha if you used something like that it could rule out scale variations at least.

After changing my process and using the weights every time I find my loads are much more consistent. I use Redding number 2 scales.

Chuck the beam scales in the same spot every time and zero before each use.

Starting to think I'm losing it too!

New brass all the same brand? Can be large volume difference brand to brand
Have you checked case trim length ??

Originally Posted by 6mm ackley

New brass all the same brand? Can be large volume difference brand to brand
Have you checked case trim length ??

Yep - all Norma brass and trim after each firing.

Are you using magnum match primers? Bit more expensive but more consistant. How many rounds down the barrel since new?

Originally Posted by Walker

Are you using magnum match primers? Bit more expensive but more consistant. How many rounds down the barrel since new?

Nope, just using the federal large magnum primers but could go to the match ones.

Honestly, couldn't tell you how many rounds. I got it almost new maybe 8 years ago. Did a fair bit of hunting but no range time - maybe 100 rounds or so over that time. Then I would have put another at least 150 through it since start of last year since I started hunting more and reloading.

Have you owned rifle since new ? Do you know how many rounds through it ? Are you using a suppressor?
Suppressor will add to any carbon fouling issues.
Cleaning with Hoppes, so long you allow goood soak time and plenty of bronze brush work once you’ve removed the Hoppes and repeat multiple times will deal to most carbon fouling. But you might need to go to a strong cleaning agent like K2 or K4, or Boretech Eliminator. If the round count is 100 plus then you might want consider polish of bore with JBs or Autosol.
But for more serious copper fouling Hoppes won’t cut it, Boretech Eliminator is my go to. Observe copper removal in the lanz for muzzle.

Like others have said loads of 2217 north of 71gn are certainly betting close to max pressure.

Originally Posted by chainsaw

Have you owned rifle since new ? Do you know how many rounds through it ? Are you using a suppressor?
Suppressor will add to any carbon fouling issues.
Cleaning with Hoppes, so long you allow goood soak time and plenty of bronze brush work once you’ve removed the Hoppes and repeat multiple times will deal to most carbon fouling. But you might need to go to a strong cleaning agent like K2 or K4, or Boretech Eliminator. If the round count is 100 plus then you might want consider polish of bore with JBs or Autosol.
But for more serious copper fouling Hoppes won’t cut it, Boretech Eliminator is my go to. Observe copper removal in the lanz for muzzle.

Like others have said loads of 2217 north of 71gn are certainly betting close to max pressure.

Yep, realistically I shouldn't have got excited and even tried to follow those higher loads but as I had no or minimal pressure signs I thought it might be ok.

I have owned it since it had about 20 rounds through. It does have a suppressor and I'd say the round count is well over 100 without ever having a very good clean. Might be time for a good clean then start the development again by the sound of things.

Is there any specific technique to get rid of the carbon ring, if it does have one?