Reloading 6.5 Grendel -- what am I missing?

[wemtx]

I just started reloading and after some success with pistol cartridges, started after the 6.5 Grendel. Ammo is hard to find and choice of projectiles is pretty limited, so before I reload more mainstream calibers, I thought I'd start with it.

The problem is, my reloads don't group. I don't mean they group poorly -- they shoot patterns. If there's a group, it's 12-18" across. The same rifle (and shooter) will shoot small cloverleafs with cheap Serbian ammo so I'm baffled.

Load data is out of the 51st edition Lyman manual -- 100 grain ELD-VTs over CFE-223, COAL of 2.245". Brass is all once fired, from the same lot. Trim length, neck tension, runout, primer depth, charge weights all check out as being consistent within the limits of my measuring instruments. And they're right on the manual figures.

What gives? What am I missing?

 

[Alistair]

Hmm.

A couple of questions:

- Perhaps an obvious one, but you say the rifle shoots factory just fine. Have you tried using some since you started the reloading stuff? Want to rule out a recently dinged crown or a lost land or something as a root cause.
- What primers are you using?
- Are you full length resizing the cases?
- Is this in a bolt gun or an AR type? If it's an AR, have you tried manually slotting a couple rounds into the chamber? Wondering if you might have insufficient crimp and the bullets are moving or something.
- Those single fired cases you're using, they wouldn't happen to be form the aforementioned cheap Serbian ammo would they?

100gr bullets, even an ELD shouldn't be giving you twist rate issues, and COAL seems reasonable, according to the manual at least.

 

[112Savage]

I couldn’t get what I would call consistent or good groups from my 6ARC with the 80gr ELDVT. They weren’t 12-18” groups though.

If you’re picking the 100eldvt for use on coyotes. Try the 95gr V-max. Its design may be more forgiving. If you just want to load to learn. The easy button in 6.6 Grendel is 123ELD/X and 28-28.5 gr IMR8208xbr.

I would also make sure you’re not over sizing your cases. For gas guns moving the shoulder 0.003-0.005” for bolt guns 0.002-0.004”. If your reloads are having significant vertical spread it could be due to over sizing and pushing the shoulder back too far.

 

[DaddyFlip]

There aren't any 100-grain ELD (Match or VT) in the Lyman 51st. Did you mean the 123-grain? What's the twist of your barrel? Describe the cheap Serbian cartridge...

 

[Robmill70]

I use the 123gr bullets in my 6.5G, they have been giving me MOA groups

 

[Gomer]

Do you use a suppressor or other muzzle device?

 

[wemtx]

Hopefully I've captured all the questions:

- Donor cases are from PPU blue-box PP6GH (120gr HPBT), which the rifle shoots brilliantly
- Primers are Federal
- Correct -- I was mistaken. Load data is from Hogdon, though I must've read that Lyman manual 100 times looking for answers, so that's why it was in my mind
- Hogdon says trim 1.515", and that's what they measure
- Twist is 1:8
- A2-style muzzle device on an AR -- if we ever get suppressors as easy to buy as foam earplugs, I'll have one
- Full-length resizing

112Savage might be onto something. I'd characterize the groups as having much more extreme vertical variance than horizontal.

Thanks everyone!

 

[Gomer]

Hopefully I've captured all the questions:

- Donor cases are from PPU blue-box PP6GH (120gr HPBT), which the rifle shoots brilliantly
- Primers are Federal
- Correct -- I was mistaken. Load data is from Hogdon, though I must've read that Lyman manual 100 times looking for answers, so that's why it was in my mind
- Hogdon says trim 1.515", and that's what they measure
- Twist is 1:8
- A2-style muzzle device on an AR -- if we ever get suppressors as easy to buy as foam earplugs, I'll have one
- Full-length resizing

112Savage might be onto something. I'd characterize the groups as having much more extreme vertical variance than horizontal.

Thanks everyone!

Is the flash hider loose?

 

[112Savage]

Check to make sure your flash hider is tight.
Check your shoulder bump versus fired cases. You could easily make a “case comparator” if you don’t have one by sizing a 375 caliber case I.e. 375H&H and zeroing your caliper on it. Then insert your 6.5 Grendel case neck into the 375 case neck and compare fired cases to sized cases.

Or just buy a Hornady comparator tool.

Last thing could be OAL is causing tips to bust during loading/ recoil. I have had this happen in 6ARC with 90gr TGK’s. This isn’t necessarily OAL issues as it is magazine/feed ramp issues.

 

[wemtx]

Back at it after a short stint away -- including 9 days with Khomas Highland in Namibia two weeks ago. I'll write a trip report and some lessons learned from my first DIY Africa excursion.

Fortunately, the sorry Grendel played no part in that hunt.

I've checked all the recommendations. Shoulder bump is 0.004" back from fired. COAL is 2.245" Everything checks out for every bit of detail I can measure. Groups at 100 yards are -- not kidding -- larger than my 12" square sighting target. By contrast, the same projectiles, launched by Hornady factory ammo, on the same day, from the same rifle run 0.6-0.75" 3-shot groups at the same distance. Even S&B, PPU, and Frontier shoot less than an inch.

What I really want to do is load 30-06 and 45-70, but I'm not inclined to spend 3-5x more per cartridge on consumables to scatter bullets over two ZIP codes. That's also why I'm not chasing powder, primer, projectile variations for the little Grendel. I figure $100 should, before I run out, produce ammo that at least all shoots within the same acre or two, then I'll start experimenting.

Any Houstonian Grendel reloaders willing to trade pizza for instruction? I've worked machine shops, rebuilt engines, made telescopes -- I don't know why reloading is more finicky or detail-driven than that, but apparently it is.

 

[DaddyFlip]

Chamber rounds from the magazine and eject them without firing. Measure COAL before and after; maybe your crimp is no good? How are you crimping? Measure bullet diameter before seating; are they to spec?