6.5CM Barrel Break-in Weekend

TRAINING LEAD-UP

Wednesday, Mar 26:

18A "Lower Body Prep" in 19:43, "Kettlebell" in 39:39

Thursday, Mar 27:

4 mile ruck using a 40# weight vest, wearing mACV1s.  My body wanted cardio and leg work.

Friday, Mar 28:

18A "Lower Push BW" in 41:53, "Hanging Abs" in 17:13

BARREL BREAK-IN WEEKEND

Saturday, Mar 29:

Now that I had my new 6.5 barrel installed the previous weekend in Virginia with Rifleman's Outfitters, it was time to get to work, breaking it in before the May 2nd Real World Sniper Challenge match.  A month isn't a lot of time.

Since I had switched calibers, even though it was the same chassis, I had to get a brand new zero.  I had to shoot rocks to get a rough idea of where I was, to get to zero.  I got there in 10 rounds, though.  The difference between the two calibers and two barrels was 2 up and 2.6 left.  The left part is a bit surprising.

I started shooting groups, gathering chrono data.  To not waste the opportunity to train, I did build and breaks from standing up to prone and from standing up to modified prone.  With about 1000 DA, my starting chrono was about 2578fps. 

I cleaned after 10 (2578fps), then 20 more (2589fps), then 30 more (2613fps), then 40 more (2619fps).  My build and breaks mixed in kneeling.  

Lots of shots, lots of cleaning.  Not as much cleaning as it felt like I had done the first time I broke in a barrel with an actual procedure, with my 2nd RPR 6CM, though.  In the long range community, there are so many different approaches to barrel break-in and especially barrel cleaning frequency.  Nobody really knows the answer about what's best.  It's hard, because every barrel is different.  Barrels are ever-changing as you shoot them and consume its life expectancy.  You can't really do good experiments, because you're working with a sample size of 1 every time.

I might be cleaning in an overkill way, doing full cleans following the Boretech process, vs running a few patches through, but after my first RPR 6CM with Hornady ELDMs started having bullet jackets come apart 30yds from the barrel on a barrel that I didn't ever properly break in, I'm playing it safe.

Sunday, Mar 30:

After day 1, I was 100 rounds in on the barrel.  I still needed another 100 rounds before the barrel would be broken in, perhaps (also a hard thing to define).  Instead of continuing to work on paper, though, I decided to try hitting some steel.  That would give me a better feel for how this caliber shoots from this gun, too.  Steel is big enough that little deviations won't matter so much, for the purposes of barrel break-in where you're not being scored and it's OK if you do happen to miss.  The dope actually worked out well, though.

I started what I call "the forest bay", and I hit targets at 165, 230, and 450yds, but there wasn't much else to shoot at, so I moved on afterwards.

I spent the rest of the day at what I call "the western bay", where there was a better variety of props to choose from.  I shot at 530yd, 510yd, 700yd, and 730yd targets, and the dope did great!

This was also a chance to test 6.5CM mags... the polymer MDT 10rounders would have their spring and followers pop on me at around round #5, oddly.  The metal mags did fine.

I shot from all kinds of positions... from rocks, logs, tires, pogo stick, VTAC with tripod rear, and modified prone table.

Since I had fun editing my last video, I decided to put together a quick little one capturing the barrel break-in day, too.

I did clean more, after another 60 rounds.  I shot 25 more after that, putting me at 185 rounds and ready to start getting official dope.  I was now at 2633fps.  I stopped when I began missing, unsure of whether it was wind or my gun.  No point in pursuing diminishing returns or even harmful returns.

I had put in 13 hours this weekend (8 on day 1, 5 on day 2)!