If you’ve been shooting rifles for a long time, no doubt you’ve said to yourself at one point: “I can’t figure out why this rifle won’t shoot!!!”. This story documents “one of those times” for me. I recently got a HOWA 1500 heavy barreled action in 6mm Creedmoor from Brownells, and built up a pretty nice rifle around it. I didn’t expect “instant satisfaction” with this cartridge: I know 6mm Creedmoor can be “particular” with loads and even things like bullet seating depth. In the end, this rifle didn’t meet my requirements- so I decided to re-barrel the rifle at just 300-350 rounds of shooting. In this article I’ll outline the steps I went through to rule out the factors not related to the barrel/bore/chamber.
The Rifle as Built
Starting with the HOWA 1500 Heavy-Barreled action, I put together the following rifle package:
- KRG Bravo chassis with enclosed forend, barricade stop
- KRG AICS-style 308 Winchester magazine
- Mystic Precision MPOD bipod
- Benchmark tactical style clamp-on muzzle brake (opened up to 0.263″ on my Precision Matthews lathe)
- Delta Stryker 5-50 power scope
- MDT 20 MOA scope rail
I have really been liking this rifle, everything except the groups I have been getting! The following sections outline the process I went through to diagnose the accuracy Issues.
Working Up a Load
Like a lot of rifle shooters, the place I start in my “journey to accuracy” is by working up a load. I had already selected a bullet to work with: Hornady’s 108 grain ELD-M bullet, a favorite of PRS shooters. The first concern I had with this rifle came when I measured the Cartridge Overall Length (COL) corresponding to where the bullet would be “touching the lands”, which was 2.866″. The problem? The COL spec for 6mm Creedmoor maxes out at 2.800″, the maximum length for magazine-fed 308-and-derived cartridge chambered rifles like my HOWA 1500. This would mean that I’d have at least 0.065″ of jump before my loaded bullets would touch the lands. And after inspecting a test cartridge, a 6mm Creedmoor cartridge loaded with a 108 grain ELD-M bullet would not have enough bearing surface in the case neck when seated to 2.865″. There would be no easy solution to this challenge- with the factory barrel this would be a compromise no matter what.
Here are some of the specifications I recorded before developing my 108 grain ELD-M 6mm Creedmoor load:
|Bullet G1 BC
|Bullet G7 BC
|Reccomended Twist Rate
|To-lands distance (COL)
While shooting my first groups with this rifle (during initial load development) I saw some inconsistent and sporadic changes from one group to the next. Here’s an example:
At first, I thought these results were a result of the “charge weight sensitivity” of the 6mm Creedmoor cartridge (friend Bill Marr of http://rifleshooter.com had warned me). Following an OCW load development model, I had loaded charges 1/2 grain apart and shot groups. Could 42.5 grains be a horrible load and 43.0 grains be a decent load? I decided to re-shoot two charge weights that produced relatively good groups for the first run-trough of this OCW testing. What did I find? These results were not repeatable! Things were all over the place.
Switching Out Components
OK, if the first load didn’t produce good results, how about switching out components like the bullets being used?
Above are the bullets I used with different load work-ups, from left to right:
- Berger 6mm 95 grain Classic Hunter
- Berger 6mm 105 grain Hybrid Target
- Sierra 6mm 107 grain Match King
- Hornady 6mm 108 grain ELD-M (original load work-up)
I wanted to make sure I wasn’t missing a specific class of projectile (bullet profile, weight, etc) that this HOWA 1500 would show a preference for. During my trials for these bullets ALL OF THEM showed a tendency to shoot about 1″ groups, very consistently. Very strange, and not a good sign.
New Brass, 1x Loaded, 2X Loaded, Small Rifle, Large Rifle
There are so many factors related to brass that can affect groups, so I decided to work with a few of these variables to see if any of them would result in consistent good groups:
- New brass -vs- 1x fired -vs- 2x fired
- Neck-only sized reloads -vs- full-length sized reloads
- Small rifle primers (Starline) and large rifle primers (also Starline)
- Brass brand (part of factory ammunition testing with Hornady ammunition) – Starline -vs- Hornady
None of these brass factors affected group size in a meaningful way. On to the next tests!
Epoxy Bedding the KRG Bravo
One of the things I’ve learned about the HOWA 1500 is that its flat-bottom action isn’t the best for consistency in terms of how it sits in the rifle stock. For this reason, it’s not a bad idea to glass-bed or epoxy-bed your HOWA action to your stock. So I went about doing this with input from Bill Marr from http://rifleshooter.com and Ron Sinema at Benchmark Barrels. I also watched Curt’s glass-bedding video over at Vaughn Precision for some pointers as well.
One of the tips I found online was to use Hornady One-Shot as a mold release agent (you can also use Pam, or car wax). This worked out great! Here’s the action taped up prior to the actual bedding procedure:
Unfortunately, this bedding job did not improve the groups so far as I could tell. On the bright side, it’s work that will help out even when the barrel is replaced since the bedding job I did only involves the action and stock mating surfaces.
Shooting With and Without Muzzle Brake
A muzzle brake can shift a rifle’s point of impact, and it can also affect the way a rifle shoots. I was pretty sure that this Benchmark Tactical clamp-on brake wasn’t causing the accuracy issues I was experiencing, but I had to eliminate EVERY possible factor. So I shot the rifle with and without the brake attached. The result? No change in group size. One more thing to cross off the list!
Cleaning Bore: Copper Fouling, Carbon Ring Checks
Above: the bore as inspected prior to shooting, very nice finish and no problems detected.
I thought it would be a good idea to inspect the bore for excessive copper fouling, and for a carbon right just ahead of the rifle’s chamber. I didn’t see anything with the borecam that stood out, but cleaned the bore and chamber really well just in case. Again, no change in accuracy after this inspection and cleaning. This was an important factor to rule out since it’s common to see an improvement in group size if a bore has excessive fouling or a carbon ring.
Swapping Out the Scope
Above: the Athlon scope I used as an alternate optic during testing (seen here on my custom 224 Valkyrie AR-15).
The Delta Stryker HD 5-50 power scope on this rifle has been awesome, but I had to try swapping this scope out for another to rule out any tracking difficulties that may have existed. I installed an Athlon 6-24x50mm scope that was known to hold zero, and again, no difference in group size. Exactly the same behavior! The Delta scope was not the issue at all…
Shooting Another Rifle, Same Conditions/Setup
Above: My trusty 224 Valkyrie Remington 700 custom build.
When I’m having a bad shooting session, I’ll tend to bring out the Remington 700 bolt-action 224 Valkyrie rifle I built here on Ultimate Reloader. It’s known to hold less than 0.4″ 5-shot groups at 100 yards if I do my part. And that rules out weather conditions (including boil), shooting support, and myself as factors. When I shot this 224 Valkyrie rifle along side the 6mm Creedmoor HOWA 1500, I was able to hold 0.220″ – 0.350″ groups consistently. While that makes me feel good about the Rem700 and my own shooting, it doesn’t make me feel better about the HOWA! It only confirmed that something was “off”.
Here’s one of my “sanity check 224 Valkyie” test groups:
Testing Factory Ammunition
Friend Matt Hornback told me while discussing these rifle issues “better shoot some factory ammo to rule out your handloads”. Not a bad idea- Hornady knows what they’re doing when it comes to ammunition, and if a rifle can’t shoot Hornady match ammo well, you need to look real close at things. So I picked up some Hornady 108 grain 6mm Creedmoor match ammo:
I shot two groups with this factory ammunition, with both of them at about 1″. Here’s an example:
OK, now things are really pointing towards a re-barrel. I ruled out just about every factor I could think of, and nothing really helped much in the process.
Consulting with Industry Pros, Conclusion
It’s always great to have people that you can get input from in the industry. Some of the people I talked to included:
- Bill Marr from http://rifleshooter.com
- Ron Sinema from Benchmark Barrels
- Matt Hornback from the MDT team
- Jesse Redell from R-Bros rifles
- Ryan Steacy from International Barrels
- Jason Duncan from JGS Precision Tools
I walked through some of my issues and troubleshooting with each of them, and concluded that I would re-barrel the rifle.
Here were my reasons:
- A factory HOWA 1500 on average will shoot 0.7 MOA-ish, possibly better, this isn’t good enough for me! And I was seeing 1″ groups on average, so my HOWA is sub-par.
- The 0.065″ minimum bullet jump scenario is not ideal, I really want to be able to load to-the-lands if I need to.
- A match-grade barrel is one of the best upgrades you can make to a rifle.
So I’ll be re-barreling the HOWA 1500, at only 300 rounds into my “relationship” with this rifle. I’ll be chambering an International Barrels blank with a custom reamer from JGS Precision. Should be AWESOME! More updates on that in the coming month or so.
Have you had success troubleshooting a rifle with accuracy problems? I’d be curious to get your input. Please leave a comment!
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