Thread: Pressure issue resolved 7mm08

I thought I'd share a recent reloading experience in case it helps anyone else out - I certainly spent a lot of time scouring forums to find a solution.

I recently got back into reloading after about at 10 year hiatus. I'm running a fairly stock standard 7mm08 Howa, surpressed, trigger tweaked, bedded, with an Arken scope. Due to a move, most of my current hunting is in the Ruahine tops, with shots ranging from 150+ metres. Furtherest to date is 325m.
As I have access to a good range, I thought it made sense to get back into reloading to get better equipped for those longer shots (both in accuracy and terminal performance).

I settled on the 162 ELD-M, using 2208 in Win brass, and RWS primers. A mate suggested a load he had found to work, and I also spent a lot of time consulting forums to get a sense of where I might need to be powder charge wise. Also got into GRT, which proved helpful. Most folks seemed to be running a little over book max, which I was reasonably confident would be fine, but I thought I better do a pressure ladder to be safe. Pressure ladder looked fine up to a grain over max, with velocities in the expected range.

I picked a couple of charge weights to test below the value I had tested to and started shooting groups. Accuracy was ok, however what started showing up was some notable pressure signs - flattened primers, stiff bolt, case head marks, elevated velocities, and often fairly signficant flyers. What was strange is it didn't show up on every shot, maybe 50%.

Thinking that I must be over pressure, I dropped charge weight 0.5gn. This showed some improvement, but was still getting occassional pressure signs, which left me feeling uneasy. I dropped charge weight again, to well under book max, yet the problem continued. I spent a lot of time measuring every possible variable that I could on the overpressure cases - case base to shoulder, trim length etc. I then did the logical thing and gave the barrel (what I thought was) a thorough clean - no improvement - if anything, things were getting worse. By this point I was over 100 rounds deep into my "load development", and felt like I had nothing to show for it.

Further research led me to the possibility that it was a carbon ring causing the issue. I did another clean that I thought would help, even using a bit of autosol, but still no improvement. I decided I couldn't really sort this properly without seeing what I was actually doing in the barrel. Being a frugal character, I bought a $9 Ali endoscope, and managed to reduce focus distance with a lens from a Kmart microscope I 'borrowed' from one of the kids ("it was never very good anyway..."). Sure enough there was a distinct carbon ring, tracking quite a way back into the case neck area. Doing some targeted cleaning with a bronze brush (rotating it), and some patches with autosol, I eventually got the large majority of it cleaned out. I learned a lot about what it actually takes to clean hard carbon through this process.

Back to the range - and success. Much lower velocities, no pressure signs, and accuracy seemed to be on point. It proved an expensive learning in terms of components spent, but was happy with the end result.

Pic below was first three shots on a clean barrel last night. Velocities 2520, 2534, 2515. I've shot a couple of similar sized groups, but most average around 0.8moa. Plenty of accuracy for my purposes - impressed with the Howa.