It's been quite a while since I've used any 95gr, but they do kill hogs well and like the 110gr are pretty accurate in most barrels. I've been testing our new tipped bullets a lot, especially the 115gr TXC, but it seems I just keep going back to the proven 125gr CC as my "go to" bullet for hogs and deer.

So I finally started loading and got good and bad results. My rifle is an M17S by Ken McCalister of K&M arms rebarreled to 7.62x40 and now to .300 HAMR. I had my smith try to cut the chamber a bit deeper, but ultimately had to go with a new barrel (old barrel was a Bartlein 1-10, current barrel is a 1-10 blank that they had but they only buy Lilja, so I think that's what it is). I started with HDY 150 SP bullets over CFE BLK and was pleasantly surprised that the gun will now cycle without a can even with lighter loads. In 7.62x40 with a 17" barrel, it would only cycle 30% of the time without a can. Velocities were great, and I slowly pushed to 26.3 of CFE BLK without pressure signs (I'm using Rem #7.5 primers, which are notoriously soft anyway). So at 26.3, I'm getting 2261-2275 over a 20 shot sample (Labradar doesn't catch everything), so I was very pleased with an ES of 15 at a max load. Brass was all Starline virgin with nothing done to it COAL is mag length, 2.25"

I brought a mag out to get it sighted in but found that the precision wasn't great, something like 6-7 MOA at 100 yards. I am using a Leupold HAMR 4x which isn't a benchrest scope but more than sufficient to print an MOA group at 100 yards. I'm shooting from an Atlas bipod on a bench. The construction of the M17S doesn't leave many places for wiggle, as it's basically an aluminum extrusion with the barrel bolted to it at the trunnion and gas block. The picatinny rail is bolted to the top of the extrusion and the scope is attached to that. All of this testing was done without a suppressor....I like to be certain of a load before I risk a can on it. It has been a project since day one, but with minimal effort it has shot minute or so groups with the 7.62x40. Bottom line, there aren't really any places for the bore to scope system to wiggle loose.

I have a few ideas. Overspinning bullets is generally a "I lost .5 MOA and lost my F-class match" problem, so I'm less concerned about the 1-10 vs the 1-13 that Bill uses. The velocity SD/ES are sufficient for a PRS load, so that's not the issue. The Hornady SP bullets have VERY irregular points, but they don't look any worse than any other spire point Hornady to me. Further, occasionally Ill get a misfeed where the tip just gets mashed, and those shots aren't really outliers. I don't have much room to play with seating depth, and velocity variation isn't the issue. I only shot enough of the 150 grain SSTs to get a safe max load, so I haven't shot a group with them yet. If the issue is the tip shape variability, that will fix it. If that doesn't work, then I thought about loading the fireformed cases. I assumed that the virgin Starline would give acceptable carbine precision, but if it needs to be fireformed then that's an easy fix. I have annealed maybe 3000 .300 BLK and 7.62x40 cases (I wish I'd known about the .300 HAMR when I started this journey back in 2017, but I didn't), so annealing 1k more is a minimal effort. Finally, I am open to other bullet ideas. The powder type, charge and primer all seem to be okay based upon the very low velocity ES/SD, so I'm not itching to change that. Seating depth is more or less fixed by the AR15 magazine, so limited room to play with that.

Any thoughts or ideas are greatly appreciated.

I shoot the Hornady 150s about 1900 fps 1:10 18" BO carbine. @ 50.
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Probably cause I don't trickle loads. IIRC, just used bags on the front. Pushed the 125 too hard. Doubt its the twist or bullet. 155 Amax does as well and I have used it @ 100.

When we started the HAM'R project I thoroughly tested 1-11, 1-12, 1-13, 1-14 and 1-15 twist rates. Pretty much across the board with 110-150gr bullets the 1-15 shot the best. These initial test bbls were mfg from Shilen blanks. We did some testing between 4 groove and 6 groove and settled on 6 groove as being the best.

Your barrels are now made in house from bar stock, correct?

duffas, Please do not take this wrong, I'm just bringing up a few points that just jump out to me.
One of the main problems with the Black Out is their twist rates. There is just too much of a spread between a decent twist rate for the light super-sonic bullets and a good twist rate for the heavier sub-sonic bullets.
I've got a couple of 1-12 barrels that will shoot decently, but my 1-15 barrels give me the best accuracy with the 110 gr. to 135 gr, bullets.
Also, any time I am testing for accuracy I will shoot at 100 yards just so I can compare the results to all of my rifles no matter what they are chambered for.

I'm booking a deer/hog hunt in Ga this fall. When I get done traveling for work, I will have plenty of time to finish getting this rifle together and working a load up. Thinking 125gr max expansions or 130HCs for the hog and 135 FTX for the whitetail.

MarduroBP - sometimes it takes a little time to work things out. Bullpups aren't known for their accuracy, but that is usually to blame on extra linkage to connect trigger to hammer.

Regardless of virgin brass or fire formed, it has been my experience that Starline's 300HAM'R cases have no issues. Your ES is saying that your load looks good. Some other common causes:

1) Inconsistent Bullet Tips (Lead Tips Smear) - Check to see how you rifle is feeding the 150gr SP from your magazine. Sometimes a rifle has a poorly shaped feed ramp that can damage a bullet tip while feeding. Next, try a different bullet, such as 125gr TNT, to determine if it was the bullet or something else. The 125gr TNT is accurate and easy to reload.

2) Issue with Rifle - If shot to shot your hits are randomly bouncing around then your target is indicating that something is Loose.
(a) Check your Scope (rail, base, or rings) and then go fire 10-20 rounds of 125gr TNT to see if still an issue.
(b) Check your Barrel starting with the Crown and then check to see if something inside the rail, such as screws for the bipod attachment, is making contact with barrel while bipod is under load. Last, check whether the barrel is loose (barrel nut or even barrel extension to barrel).

3) Shooter Error - challenge of recoil management with a short rifle using a bipod on top a shooting bench (minimal traction), which can result in the rifle bouncing during shooting (spring board effect). You may not notice this happening so ask someone to watch from beside you or set up your phone to record you shooting a few shots.

We mfg the following from USA 416R bar stock from start to finish, including HT and double stress relieve:
.223/5.56
.22 Nosler
224 Valkyrie
6mm ARC
.243 Win
.260 Rem
6.5G and 6.5CM
300BLK
300 HAM'R
.308 Win
350 Legend
9mm

We mfg the following from "premium" Shaw rifled blanks:
.204 Ruger
6.8 SPC
7mm08
.338 Fed
.358 Win
.458 SOCOM

I really appreciate all of the advice, I just picked this post to reply to as it is the longest.
1) I agree and hope that this is the issue; if it proves to be the problem, then my SST loads should shoot fine and problem solved.

2) A few points: This is not an AR15. I didn't do a great job of describing it above, but you can look at any of the info on the new M17S. Basically its a greatly simplified version of the old Bushmaster M17S. That has pros and cons in terms of precision. The barrel is attached to the extruded aluminum upper via through bolts at the trunnion and gas block. It is far more secure and positive (i.e. if the bolts are tight then it's easier to destroy the upper than separate it from the barrel) than an AR15, BUT there is no way to free float the barrel. The picatinny rail is bolted to the top of the upper extrusion and the scope attaches to that. Bottom line, the lack of a free floating barrel puts a ceiling on precision, BUT there are basically no parts that can be loose or wiggle without being obvious. My aim is a 50-250 yard rifle, and the precision limit at 1.5 MOA are just fine for that purpose. I agree that it's never bad to recheck for loose stuff, I just don't have high hopes of finding my issue there due to the reasons listed above. As for looking at the crown, that's a great point. I didn't get a great look at it because the smith reinstalled my muzzle brake (it's a Gemtech adapter/brake combo, so you have to rocksett it in or you sometimes wind up with a makeshift thread on can that you didn't plan on. I can't say for sure that there isn't a burr on the crown, and I should check it.

3) This is always a threat and we would all do well to stay vigilant about it. I was hopeful that this was the issue because it's free to solve. However, my hopes are pretty low. I do all of my load development prone on a bipod....this session is the first time that I have used a bench in a year, and that was mostly because the labradar is hard to balance on the foam shooting mat. This practice adds a degree of noise to precision measurements which means that I can find absolute best load only via chance. However, I can and do shoot sub MOA prone from a bipod on a regular basis, and the benefits are 1) useful practice while developing loads and 2) I have real world data for the sum of my wobble off of a bipod plus the gun's dispersion. That's an entirely separate discussion with many correct answers, but I bring it up only to illustrate that the 6-7 MOA that I saw the other day is a far cry from that I know that I can consistently do.

Bottom line I think the "simple stuff first" approach is great, and I'll get a box of WT 150 SSTs to test alongside my own loads.

Thanks for everyone's time and attention. I'll report back with some data and hopefully pictures in a week or so.

I sure wish you made a shorter .260 Rem barrel. I prefer it over 6.5CM but I walk a lot and shorter barrels have just worked better. I will have to settle for the Creedmoor I suppose. Which reemer is used on the 6.8SPC?

Ever try the Grendel?

I tried the Grendel. It's just too slow for my liking. Accurate yes. Just with it was up around the 27-2900 range in velocity.

Spinaltapp, The 6.8 was the first non-.223/5.56 caliber we offered and we've always used a PT&G 6.8 SPC II reamer with a 1-11 twist

Sorry I'm late to the party on this one but for some reason my browser doesn't automatically change the page and I didn't notice I was a couple days behind.

One thing that happened to me that hasn't been mentioned yet and is so rare and bizarre that it's about like getting hit by lightening is I had a barrel once that the face of the threads wasn't perfectly flush and when I screwed on a suppressor the POI shifted down and to the right about a foot because the bullet was hitting the exit hole on the way out. If you check everything else out (the easy stuff) and still can't find the issue you might want to take off the muzzle brake and see if it makes a difference.

Bill, was wondering if you could give me a idea when you might due a run of the 7mm08 barrels? I asked a sales rep over the phone and they didn't have any idea.

We have the barrels, they are in the final blast/laser stage, they just aren't in the warehouse yet. If you place an order you will receive one quickly. Tks

Bill, thanks for the quick reply. This will be my fourth barrel from your company. Y'all do a fine job, all of them capable of sub MOA.

I’d like to order a 11.3” Ham’r barrel while they’re on sale, but the website doesn’t give the option to backorder. Will they be in stock again soon?

Sierra 2020 125gr flat nose hollow points are back in stock at midway if anyone wants to try them. Link

Greycard - I can't walk the 100 very often, body is old. I posted this to show that the 1:10 will handles most Hamr weight bullets well enough, maybe not perfect but OK. I don't shoot subs, see NO reason. If I need 200yd shots I'll take the 308W. Shot a walking hog with IR/BO thurs eve, 135 FTX. Funny, it wandered around in brush/trees for about 5 min, back & forth. Didn't run off. Also got an armadillo the night before @ 50 yds, same rig. I've got a 1:8 BO I use for 185gr cast. shoots fine but getting enough fps to get spin up is tougher. Basic reason I don't shoot subs. I like the idea of the Hamr, just don't have enough usable yrs left to make it worthwhile.

I finally got to a project that I've been wanting to do for quite awhile, just never seemed to have time to do it.... I tested the 12 most popular bullets used in the 300 HAM'R today for a basic comparison of terminal performance in spite of some rather crappy weather.

TEST PROTOCAL:
The velocity of all loads were basically the same as the WC factory loads.
All bullets were shot today out of the same 16.2" barrel.
All bullets penetrated a 1" dense closed cell foam "bladder" into a 48" deep water tank which I've proven over and over gives almost identical results compared to gel.

OBSERVATIONS:
The Speer 110gr SP, 110gr Lehigh CC2, Lehigh 125gr CC, Speer 135gr Bonded, Hornady 135gr FTX, Speer 150gr Gold Dot (Blackout version) and Hornady 150gr SST all performed very well in my opinion.

The Hornady 110gr SP and Sierra 135gr HP-V came close so I'll give them honorable mention.

I was disappointed with the performance of the Speer 130gr HHC and Speer 150gr SP at 200yds. No expansion on the SP and one of the HHCs hit the end of my 48" deep tank?

I was very surprised that one of the Hornady 110gr V-MAX bullets didn't expand at 200yds while the other 3 "exploded" like a normal varmint bullet???

Both Lehigh bullets performed exactly like the always do and reminding me why the 125gr CC is my personal "go to" bullet for deer and hogs.

As I already knew, for big animals over 400# the Speer 135gr Bonded and 150gr Gold Dot are the best choices.

I really like the looks of that 135gr bonded. It's what my brain expects a recovered hunting bullet should look like. It was fairly beaten into my head from a young age (now 56) that traditional expansion and weight retention were the prime attributes of a good hunting bullet. The CCs are so contrary to that idea that my brain twitches when I see a bullet come apart like that.

Full weight retention is great for bigger game, but for whitetail deer and hogs the CCs kill like LIGHTNING !!!

Thanks for doing this Bill!

This confirms a lot of my testing that I have done in gallon milk jugs with water that gives an almost identical result.

Posting this for the whole community is a big help!