Re-Barrel at 300? Diagnosing a HOWA 1500 6mm Creedmoor That Won’t Shoot

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:

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 Info
Bullet MFG Hornady
Bullet Family ELD-M
Bullet Weight 108 grains
Bullet Diameter 0.243 inches
Bullet G1 BC 0.536
Bullet G7 BC 0.27
Bullet length 1.265 inches
Reccomended Twist Rate 1:8
Lot number 2182207
Bullet SKU 24561


Rifle-Specific Measurements
To-lands distance (COL) 2.865 inches

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 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:

  1. Berger 6mm 95 grain Classic Hunter
  2. Berger 6mm 105 grain Hybrid Target
  3. Sierra 6mm 107 grain Match King
  4. 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:

  1. New brass -vs- 1x fired -vs- 2x fired
  2. Neck-only sized reloads -vs- full-length sized reloads
  3. Small rifle primers (Starline) and large rifle primers (also Starline)
  4. 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 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
  • 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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15 thoughts on “Re-Barrel at 300? Diagnosing a HOWA 1500 6mm Creedmoor That Won’t Shoot”

  1. I kinda miss the days when a plain ole deluxe rifle used to satisfy my shooting aspirations. After educating myself with the finer aspects that achieve precision, I have found that anything other than a custom rifle to be crude. The days of simply buying a couple of boxes of ammo and a trip to the range are now gone; except when indulging in offhand practice-lol.

  2. Gavin, I have a very similar story with a Howa Bravo in 6mm creed. Same experience with all types of hand loads. Can’t get it to group! Put a Timney trigger in, no improvement. Installed a new McGowen pre-fit barrel (1:7 twist). No improvement! Completely frustrated!! Called McGowen and without question, they sent me a production order for a replacement barrel. Great customer service, but I am honestly skeptical…will that fix the problem??? We will see. Keeping the Howa in the safe until I have the new barrel…too frustrating to keep on shooting as is. MERCY! I have MANY other rifle that I hand load for that shoot sub 0.5MOA groups all day long. I don’t get it. Is this caliber just impossible to load for? What is the deal???

    I’d love to hear from you on this. I also have a Savage Stealth Evolution in 6mm creed. I have had NOTHING but problems with this rifle too…

    BTW love your website and videos! Keep them coming!!!

    1. Companies are less prone to doing the right thing. They worry about liability and cost reduction. I’ve had bad experiences with firearms makers and at times it is like pulling teeth to get them to resolve an issue. Some times they say they resolve an issue and they don’t. Other times they will not even tell you what they did. That’s the worst of them all. When you are trying to asses what the problem is all you may do is waste time shipping a firearm back and forth. I have to agree with Gavin’s approach on this one. When going through a process of elimination to diagnose issues, the firearms maker is not your best choice.


  4. Hi Gavin,
    Hey I love your channel and videos! Why not set back the barrel to get an ideal distance to lands since you have the ability to do so? That would seem like the first step with such a big gap. And you would confirm or create parallel seating surfaces of barrel, action and lug. You would help those of us on budget to confirm how good the factory QA is on Howa.

  5. Hi Gavin, I had the exact same thing with my howa 1500 in 6 creed. Also had it in a bravo. Your on the right track with the barrel. It was fun listening to your squad cheering on at the Finely cup. Enjoy your video. Keep up the good work

  6. I’m having similar issues with my Howa 300 win mag. Can rarely get it to group any better to 1.25MOA. Mines in a Boyd’s thunbhole stock fully epoxy bedded and free floated.

  7. Had a vanguard that wouldn’t hold groups and had issues zeroing in the middle range of the scopes. (3) scopes, (3) sets of rings, and (2) different bases all with the same results. Turns out it was an action to barrel alignment issue.

  8. You probably know 41.6grs H4350 is the max with the 108s, that being said, my experience with the 6mm is that it likes about a grain or so off of max, I’d be looking to load somewhere in the 40.5grs range.

  9. Having the same problem with my howa
    1500 300 win mag my 308 win in the same stock and same scopes shoots great no problems if anyone has the answer to this problem please respond

  10. Hello Gavin:

    I have the same 26″ 6mm Creedmoor barreled action as you but mine does shoot very well. It likes 108 Hornady ELD-Ms loaded at magazine length with a stout load of H4350. Please don’t anyone take my load as a recommendation–it is not a recommendation. I shoot mine at 3130 fps. While it has been a while since you did this update, as I was watching I had this thought: You have obtained a significant amount of knowledge and experience since this review. What about cutting off an inch or so from the original Howa barrel and, using your lathe, remake the tenon, thread it and move the chamber forward with your custom reamer and see if it shoots. I know that is a lot of work but it would be interesting to see if that makes a measurable difference.

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