I've watched a lot of 300 Ham'r videos, read lots of articles, came across some forum topics, but they often end with no love for the Ham'r. I get the idea for the 300 Ham'r. I've been considering a 300 Blackout build, I do reload and subsonic is NOT something I'm all that interested in.

I have a short 7.5" AR, a 16" AR, a 24" AR and a 18" MEGA 308. I like the idea of a hard hitting, decent range shooting AR that isn't a heavy pig like my 308. I'm sure I'll eventually get a suppressor for my 308 so that would be handy for the Ham'r as well. I don't think I'll be really missing out on subsonics so I'm having a hard time finding a good reason to build something else instead. I have a box of over 1,000 pieces of 223 brass and haven't found any info saying you can't use it to make Ham'r brass.

I'd really appreciate any suggestions why to not go with the Ham'r or reasons why another round would be better. I suppose what I'm thinking about doing is to build an AR that is within reason the most AR-15 223/5.56 compatible parts wise, provides a hard hitting impact at a decent range (within 200-300 yards or so). The Ham'r seems to fit the bill with just a barrel and perhaps 300 Blackout magazines.

Because it's not THAT much different from 300blk, which is already the more mainstream option with more support.

I just thought there was actually a significant increase in impact on target in comparison to 300 Blackout due to the increased powder load and higher weight projectile.

The charts I've seen fiddle with the bullet weights to make the 300 BO look weak in comparison.  

With lighter bullets like the VOR-TX 110 grain or similar Hornady there's not much performance difference.  

Coincidentally, these lighter supersonic loads are the ones that offer best performance on deer.

I'd say that it sorta falls into the "vast sea of many similar calibers to take deer" category.

On small frames it competes with 6.5 spc, 6.5g, 350 Legend, 7.62x39, and of course 5.56.

I think it often gets compared to .300blk, but that isn't a correct comparison.  .300blk plays great in single digit barrel lengths and with subs.  The other calibers seem to do better around the 1 foot mark and above.

Guess it depends on what you are looking for.

Thanks guys, I think I'm starting to see the difference. So 300 Blackout covers the vast majority of what I'm looking for and the 300 Ham'r only covers a small niche advantage with more limited options/uses.

If you have no interest in shooting sub's, the HAM'R is your answer.  The 300 BO doesn't come close in rifle length barrels shooting super's.

I love my 3, they are all sub-moa at 100  with my 125gr tnt load of CFE blk.  I have tons of .223 brass and will never run out so it made sense to go with the ham’r so I could use that brass. If nothing else it is much more refined than the 7.62x39 , it’s more reliable, more accurate, has better bullet availability, better magazines and better ballistics although my favorite load only runs a 125gn bullet at 2400-2500 FPS depending on the rifle I use. All 3 of my ham’r s use Wilson combat barrels.

I have a couple 7.62x39 AR’s plus a 6.5 grendel but my go to rifle is the ham’r for medium game or just fun shooting.

I hear ya BOTH and that's what everyone's saying, including accuracy, but then the forums say the Ham'r isn't "that much better" and Wilson cherry picked numbers to make it 'appear' better. I know ya can't believe everything you read. I suppose reloading data is all you can rely on and a chrono tells the truth.

I'm actually looking for a relatively short barrel with a hard hitting round within 200-300 or so yards with max AR-15 223-5.56 compatibility. Just trying to justify which way to go. I'm torn between 300 Blackout  and 300 Ham'r.

I'm thinking 'I could go 300 Blackout and not miss out on the possibility of subsonics' OR I could go with a bit more geeked out Ham'r round and not miss subsonics due to MANY claimed sub MOA accuracy.

My logical mind is telling me to stick with 300 Blackout and ... build a Ham'r upper later

If you want 30 caliber and don’t care about subsonics, why not the 7.62x39?  Lots of ammo choices and far less expensive than the two you’re considering.

Sounds like the OP reloads.  I reload also.  I also have a lot of 556 brass.  That makes 300BLK and 300Hamr both appealing.  I also have a bunch of 7.62x39 uppers and like that also.  
These days everything is getting dried up...there is an active thread with people looking for 7.62x39 bolts right now.  

With BLK or HAMr just use your current 556 bolt and mags.  

One issue I have with 300BLK is that while it can do both super and sub, just doesn't seem practical for me since the point of impact is so different when changing ammo from super to sub or vice versa.
So I have a separate uppers for super and sub with dedicated and zero'ed optics for each.  

That said, if I really want better supersonic performance then the 300 Hamr appears to be more appealing than supersonic BLK especially with longer barrels.  Projectiles also appear more commonly available.  
I don't have a Hamr yet but I can see the appeal.  I'll just live with separate BLK uppers for now.

One thing that has crossed my mind is that we have all seen posts where someone chambers a 300BLK round into a 556 chamber, bullet gets set back and trigger is pulled then gun blows up.  I'm not sure but I'm wondering if that condition is also possible with Ham'r, if it isn't then that would be a plus over BLK.

I have several 300 HAM'Rs and couldn't be happier!  At the same time,  I realize that it is useless to try and show 300 BO owners that there is a better option out there if you want supersonic performance, increased energy, and match grade accuracy.
If you have a 300 BO, and you're happy, good for you.  With the number of options on the market right now, there is no reason why shooters shouldn't be content.  I've retired after 20 years of writing about knives, guns, and survival equipment.  Now I can use the weapons I want to use instead of the ones I'm reviewing, and my personal choice for a hunting or defensive rifle is chambered in 300 HAM'R.

I built a 300 blk years ago for the sole purpose of shooting 125gr bullets for dear.

The fast twist and limited case capacity made the gun meh.

Just built a 300 Hamr. Much better.

150gr @ 2300fps is the same as factory 30-30.

125s @ 2500fps

I made the brass cause no 300 Hamr brass in stock.

CFE BLK works best if you compress it as much as you can.

If your not vested in the 300 BO, go for the 300 H'mar. I would but vested in 300 BO that moving to the H'mar would cost to much. You get more powder in a H'mar case than a 300 BO.

300 Whisper (subsonic rounds in AR) became 300blk....which was designed to replace the MP5SD (and other subguns) while doing it in the AR platform with only a barrel change, and also providing more power/energy shooting supers than the Mk18.

I have no clue as to why 300 Ham'r or 350 Legend are always compared to .300blk as they were designed for completely different reasons.
Actually I do.  
Marketing....because .300blk was a commercial success, it is easier to compare the rounds to .300blk to get some of that shine.

The whole niche of .300blk is its easy of entry (just a barrel change), flexibility (subs and supers), power and manners RELATIVE to its extremely short barrel.   It isn't the best deer/hog gun.  It isn't the most accurate 30cal round out there.  It isn't the most powerful 30cal round out there.  But it is accurate enough and powerful enough to be a passable, closer range deer gun while ALSO being the closet thing to a modern day PDW that you are going to find.

Somewhat heavily vested in 6.8 SPC, barely invested in 300 AAC in 8.5" and 10.5" barrels.  I haven't seen where Ham'r is of much greater benefit in the shorter barrel length?  I am mostly interested in supers, so if it wasn't for the 6.8 SPC I'd probably be all for it.

As was already mentioned earlier, it's pretty hard to best 300BLK in sub 10" barrels. The Ham'r doesn't seem capable of doing so in that barrel length. The 110gr Barnes in 300BLK can be pushed fairly fast, and with OP looking at 2-300yds, the heavier supers may be marginal at that distance.

Once you get beyond 9" barrel length, need to start comparing 6 ARC, 6.5G, 6.8, and 300 Ham'r. I suppose you could throw legend in there as well. All IMO of course.

Also my opinion, but if strictly concerned with supers, paying attention to the other rounds mentioned makes sense. Adding a couple inches of barrel can greatly expand the capabilities of the weapon. Maybe not something you need or want, but something to consider.

Ya, more powder is of little use if you don't have the barrel length to take advantage of it.  If OP wants a shortie, there is no real advantage to the HAM'R

And THAT is the kind of info I have NOT found in my searches. They're always posting 18" barrel data. They sell 11.5" barrels, but no data for that length. I 'assumed' it would be decent, but you know what they say when you assume.

I'd prefer a relatively short barrel, good accuracy, hard hitting, LOVE the idea of utilizing my 223 brass as well as the parts/bolt & magazine compatibility.

Not displaying right on my phone, but this is straight from the horses mouth, should be a post with the short barrel Ham'r velocities. I think if you dig more, you'll find the 11.5" numbers too:

https://www.ar15.com/forums/ar-15/300-HAM-R/121-745531/#i7988700

Not everyone gets 2200fps with the 110gr Barnes out of an 8.5" barrel in 300BLK, but I do. Looks to me like the Ham'r will push the 120gr to about the same velocity as either round will push the 110, which is something. Pretty small difference, but it's there.

Thanks for that link! I'll keep digging.

300 Hamr is a great round.

It is a significant step up from 300 BLK with supers.

If you don't reload it's probably not worth it.

For dirt shooting stick with 7.62x39.

I have both, and have experimented in 8" and 16" length barrels for comparison, since I have both in these lengths.  The other barrel lengths I have aren't identical between the two.  I prefer the 300 HAM'R.  Unfortunately, you can no longer get the 8" barrel for the 300 HAM'R, but 11.3" is available now.  Whether using an 8" barrel or 16" barrel, I always get at least 150 fps faster muzzle velocity with the 110 Gr. bullets in the 300 HAM'R.  That is using factory ammo.  Hornady or Barnes for 300 BLK, and Wilson for the 300 HAM'R.  To me that is a worthwhile increase, and I get better accuracy in the 300 HAM'R.  Probably due to having an optimized twist for supersonic rounds.  I have shot heavier bullets out of the 300 HAM'R, but haven't experimented much with anything over 110Gr for the 300 BLK.  I think that the heavier bullets are where the 300 HAM'R Muzzle Velocity starts to push past the 300 BLK by up to 300 fps, as advertised.  You should look at the discussion on the 300 HAM'R on the Texas Hunting Forum for more information.  I may be wrong, but it is my impression that most who bad mouth them on this forum, don't have any actual experience with them.

300 HAM'R info from Texas Hunting Forum

458 Socom.

Just need a bolt and a barrel.

Subs using Trail Boss are quietest ever.

Supersonic hit hard.

None of your mags need hold more than 10 rounds so you can own them anywhere.

Just doesn't deal well with 200+ yard threats.

Thank you very much EVERYONE. I'm reading every comment and reading EVERY link. Don't think I haven't been searching too. I have time to complete a build and I know parts are scarce. I'm in no rush. I just feel a gap needs eventually filled between all my 223/5.56 builds and my big ol heavy MEGA 308.

I start thinking I'll just go with 300 Blackout like I've been considering for years, but then that damn Ham'r pops back in my head. I started thinking 6.5 Grendel, but I have over 1,000 pieces of 223 brass and a variety of 308 projectiles.

I think I'm going with either 300 Blackout or 300 Ham'r. I really appreciate everyone's input.

If your intention is supers go with the Hamr.

Subs, go with Blackout.

Either one of these has a benefit over other AR15 compatifull rounds because they use standard bolts and cases can be made from plentiful 223 brass.

I'll add that starline makes brass for 300 HAMR and if you order directly from them it is shipping within a few days as of last week.

It's good brass.

Making brass is fun and all but it's nice to just load up and shoot.

Just in from the range chronographing with a LabRadar, 54 degrees F

Guns used:
WC Protectors .300BLK
WC Rangers 300 HAM'R
WC Ranger 5.56
Hungarian AK
Marlin 336Y
Ruger Am Ranch

16"
.223 77gr Fed HPBT-M 2485fps
.300 BLK 135gr Horn FTX 2085fps
.300 BLK 150gr Fed Fusion 1910fps
300 HAM'R 135gr Horn FTX 2408fps
300 HAM'R 150gr Speer Bonded 2293fps
7.62x39 Rem 125gr Rem Core Lokt 2325fps
.30-30 Rem 150gr Rem Core Lokt 2269fps
.350 Legend 150gr Win Extreme Point 2183fps

11.3"
.300 BLK 135gr Horn FTX 1959fps
.300 BLK 150gr Fed Fusion 1787fps
300 HAM'R 135gr Horn FTX 2297fps
300 HAM'R 150gr Speer Bonded 2153fps

8"
.300 BLK 135gr Horn FTX 1852fps
.300 BLK 150gr Fed Fusion 1681fps
300 HAM'R 135gr Horn FTX 2147fps
300 HAM'R 150gr Speer Bonded 2003fps

The 8" 300 HAM'R 135FTX was 62fps faster than the 16" .300 BLK, just sayin ......

My original goal with the 300 HAM'R was to equal the time proven .30-30 out of a AR15 platform. 150gr 300 HAM'R 2293fps, 150gr .30-30 2269fps when shot from the same barrel length.

As a final note, factory ammo published velocities don't always reflect the velocity you will get from commonly used barrel lengths. SAAMI has 3 different "standard" barrel lengths 16", 20" and 24". The published velocity for older calibers like the .30-30 are from 24" barrels, not from the more common 20" that most .30-30s have. SAAMI standardized both the .300 BLK and 300 HAM'R with a 16" barrel.

With equal pressures, there is no replacement for displacement.  An 8" 7mm Rem Mag is going to out run a 7mm TCU.  If someone is arguing otherwise, they don't have pressure test equipment.

That's why the Ham'r is always going to outrun the Black Out regardless of bullet or barrel length.  

But if you're losing the "300BLK is better" argument, you can always throw the "efficiency" card on the table.  That's good for some bullshit bingo.

Tony

Tony and Bill, I always appreciate it when you post. 100% straight knowledge every time.

I just got back from shooting my 300 Hamr. Too dark here to get anything on the chrono but the 16" 1/13 Wilson barrel I have is already proving to be a laser and I haven't even done any load development yet. The handling and lack of recoil is likely going to relegate my 308s and 6.5 G to the back of the safe or possibly even the chopping block. So much capability for such a light and convenient rifle.

I'm currently loading 125 Gamechangers and 135 SMKs and both are looking great. I have a pile of surplus ball and tracer projos I am going to load up for blasting as well.

Bill have you ever considered doing a run of nitrided chrome moly barrels? Stainless is really nice but I'd love to have a blaster barrel I could abuse without feeling too bad.

Tony, wish you folks would make at least one barrel for bolt actions.

With 300BLK you will have a lot more choices both in barrels and production ammo. The 300 Ham'r is just a revamped 7.62 X 40 wt that Wilson came out with before the Ham'r that everyone here that doesn't like the 300BLK said the same things about. The 300 Ham'r will typically run faster with supers than the 300BLK. The speed difference starts to falter as the barrels get shorter. The real difference in the terminal effects will almost be negligible in barrels under 12 inches and even in the longer barrels does 150fps really make much of a difference in shootings that will take place typically under 300 yards? Both of them at 300 yards will be well into supersonic territory and if they are using the 110gr Barnes black tip they will both expand to 1/2 in and penetrate at least 16 inches. Meaning anything that gets hit by the 300BLK or the 300 Ham'r won't know the difference.

Most people don't run their reloads at max pressures anyways as I download my 110gr black tips around 100fps off of max load and I don't see much of any difference in capability in its terminal ballistics. The simple fact is there is very little difference between the two when it comes to supersonic but huge differences between the two when it comes to current and future availability of products. As the 300 Ham'r is a very niche round where it has a small advantage in supersonic speeds over the 300BLK and no advantage in subs. The 300 Ham'r lacking in power to other rounds that can fit in .223 mags and bolts that don't do subsonic.

Not sure where you got the 150fps #? The velocity gain of the HAMR over the BLK is very similar to the .300WM over a .30-06 and I don't know of anyone who considers that insignificant.

135FTX loads from a 16" barrel (same exact .274BC bullet in both loads for comparison sake), source of data below is the Hornady ballistics calculator, 2.5" sight over bore and 350ft elevation used, all other setting were default.

Muzzle
BLK 2085FPS, 1303FPE
HAMR 2408FPS, 1738FPE
Difference 383FPS, 435FPE

100yds
BLK 1814FPS, 986FPE, zero (already 14FPE under the often quoted minimum for big game hunting)
HAMR 2113FPS, 1338FPE, zero
Difference 299fps, 352FPE

150yds
BLK 1688FPS, 854FPE, -2.5" DROP
HAMR 1973FPS, 1167FPE, -1.6" DROP
Difference 285FPS, 313FPE, .9"

200yds
BLK 1579FPS, 739FPE, -8.1" DROP
HAMR 1840FPS, 1015FPE, -5.3" DROP
Difference 261FPS, 276FPE, 2.8"

250yds
BLK 1459FPS, 638FPE, -17.3" DROP
HAMR 1713FPS, 879FPE, -11.7" DROP
Difference 254FPS, 241FPE, 5.6"

300yds
BLK 1357FPS, 552FPE, -30.5" DROP
HAMR 1593FPS, 760FPE, -21.1" DROP
Difference 236FPS, 208FPE, 9.4"

The above #s look much better for the HAMR if you compare the 150gr SST load to any of the BLK 150gr loads, but since both bullets aren't available in both calibers I chose the 135FTX to compare apples to apples.

I've taken close to 2000 animals (over 650 in 2020) of hog/deer size or larger with the HAMR now including bull Elk, Kudu, Gemsbuck, Zebra, Waterbuck and Wildebeest, most with the 150gr Hornady SST. I know what it will do and I also know a 6.5 Grendel, 6.8 SPC or .300 BLK can't equal it as far as terminal performance on tough game.

As to availability, at least one of the major ammo companies would have already had HAMR ammo on the market if not for the current buying frenzy, now the ammo companies major goal is to produce as much 9mm, .40S&W, .45, 5.56 and .308 ammo as they can with new products being on the back burner. With SAAMI acceptance it will eventually happen.

From literally 4 posts above yours.  Number never lie.

Just in from the range chronographing with a LabRadar, 54 degrees F

Guns used:
WC Protectors .300BLK
WC Rangers 300 HAM'R
WC Ranger 5.56
Hungarian AK
Marlin 336Y
Ruger Am Ranch

16"
.223 77gr Fed HPBT-M 2485fps
.300 BLK 135gr Horn FTX 2085fps
.300 BLK 150gr Fed Fusion 1910fps
300 HAM'R 135gr Horn FTX 2408fps
300 HAM'R 150gr Speer Bonded 2293fps
7.62x39 Rem 125gr Rem Core Lokt 2325fps
.30-30 Rem 150gr Rem Core Lokt 2269fps
.350 Legend 150gr Win Extreme Point 2183fps

11.3"
.300 BLK 135gr Horn FTX 1959fps
.300 BLK 150gr Fed Fusion 1787fps
300 HAM'R 135gr Horn FTX 2297fps
300 HAM'R 150gr Speer Bonded 2153fps

8"
.300 BLK 135gr Horn FTX 1852fps
.300 BLK 150gr Fed Fusion 1681fps
300 HAM'R 135gr Horn FTX 2147fps
300 HAM'R 150gr Speer Bonded 2003fps

The 8" 300 HAM'R 135FTX was 62fps faster than the 16" .300 BLK, just sayin ......

My original goal with the 300 HAM'R was to equal the time proven .30-30 out of a AR15 platform. 150gr 300 HAM'R 2293fps, 150gr .30-30 2269fps when shot from the same barrel length.

As a final note, factory ammo published velocities don't always reflect the velocity you will get from commonly used barrel lengths. SAAMI has 3 different "standard" barrel lengths 16", 20" and 24". The published velocity for older calibers like the .30-30 are from 24" barrels, not from the more common 20" that most .30-30s have. SAAMI standardized both the .300 BLK and 300 HAM'R with a 16" barrel.

I got the 150 fps average from people that actually hand load these two with the same bullet in both for a better comparison. The other is that the round is such a niche round that there is no real ballistics chart that has the 300 Ham'r on it and I am hard pressed to take the word of the manufacture that is trying very hard to push their product by quoting the best numbers for the best bullets at the highest pressures. This is like when the 338 Lapua magnum guys say that they are more powerful than the 50BMG at 1,000 yards which can be the case if you were to compare the best 338 Lapua magnum bullet to one of the Mil Surplus ball ammo rounds for the 50BMG. But when all things are equal and you put a good bullet like the 750gr Amax in the 50BMG it destroys the 338 Lapua in every category except light recoil and gun weight.  

The fact that you used heavier bullets than what is common in the 300BLK is telling to what you are trying to achieve. As the most common .308 diameter hunting bullets designed for the 300BLK are 125gr and under because most of the heavier bullets will not expand out to 300 yards at the velocities that the 300 Ham'r and 300BLK are capable of as those heavy bullets are made for the .308 Win.

Every one of those animals mentioned can be taken with the 300BLK or even a 9mm with the right shot but it doesn't make it the right tool for the job. It just seems like you are tying to make this fit into a niche it really doesn't belong in. As for the 6.5 and 6.8 guys I don't think they will agree with your assessment but stranger things have happened.

As I said there is very little gain in going the 300 Ham'r route over the 300BLK especially in shorter barrels. Those that do go the 300 Ham'r route probably like trying new things and can appreciate the speed advantage and lack of subs without saying they are taking large dangerous game with it. To think it will be anything more than a very small niche round just look at the 7.62 X 40 WT and the other guy who was on here pushing the same small speed advantage trying to get SAAMI approval and paying a manufacture to make his ammo a couple year back that is now defunct is practically a futile effort as so many other .308 AR barreled wildcats have gone. The fact that it will never have the same wide variety of barrels, ammo, reloading equipment or support from the major manufactures as the 300BLK does will relegate those who pursue it to having limited selection or being stuck with the one or two manufactures. For those that are down with that then variety is the spice of life.

As I said earlier any living thing that these guns should actually be used to shoot would not notice the difference in the two round. When the 300BLK is capable of penetrating 16 inches with full 1/2 inch expansion out to 300 yards there isn't much of anything 250 pounds and under that will walk away from a hit like that. Yes, an Elk or Wildebeest might notice but neither of these guns are anywhere close to ideal choices for taking game of that size and anyone who says different is just trying to sell you something.

For one you don't need the actual round for a ballistics chart work up. Just the bullet and speed.

Also do your own home work on the 150fps difference.  It's from using Lil Gun in the 300blk which can give unpredictable big pressure spikes and if you wanted to try it in the Hamr you will get some pretty good velocity over what is safely posted.

The only thing the BLK is good for is quiet subs.

Recoil737, not to start a pissing contest, but I'm calling BS on some of your comments

If you want me to run the #s I will and post them, but the HAMR has the same advantage over the BLK with 125gr bullets, when I did the above chrono work I didn't have any 125gr BLK factory loads and as we all know it's not like I can run to the local Academy and buy some now!!! The HAMR will easily achieve 2530fps from a 16" with the 125gr Sierra SPT PH (with pressure under SAAMI max and consistent sub-inch accuracy), HSM loads bullet and lists a MV of 2200fps but I've never got that much out of my 16" BLK with that ammo. I'm just not sure why you don't think 300fps+ is significant???

As to bullet performance I've spent a LOT of time on this in "actual" testing, not theory. Besides killing game and recovering bullets, we've done a lot of testing by shooting through hog carcass into water for bullet recovery. The bullets we load were chosen for accuracy and reliable expansion. As an example the 150gr Hornady SST we load is the variant designed for the .300 Savage and it works like a controlled expansion bullet at HAMR velocity. I've shot two deer with this bullet at over 300yds (lasered after the shot), one was quartering so I recovered the expanded bullet the other was a pass through broadside and the exit certainly looked like an expanded bullet have exited. Trajectory wasn't an issue with my rifle zeroed at 170yds which allowed me to hold top of the back. With the 150gr Bonded (made for us by Speer for the HAMR) I shot through both shoulders of a broadside Zebra stallion. With a BLK I doubt I could place a killing shot on a deer at 300yds due to trajectory and I'm confident the bullet wouldn't reliably expand due to low impact velocity.

We haven't even really discussed accuracy, but I'll put the HAMR up against the BLK anytime for accuracy. While the common 1-7 or 1-8 twists used in the BLK severely over stabilize the 110-150gr bullets the 1-15 twist is optimal for 110-135gr bullets in the HAMR while still stabilizing the 150gr under all but arctic conditions in barrels under 16". I've got stacks of targets with sub 3/4" 100yd groups and a lot of sub 1/2". Even a few as small as .160" for 3 shots. These groups are from more than a dozen different barrels, not a select super accurate one. Show me where that can be done with reliably with the BLK with any mfg barrel and/or any load???

With 300BLK you will have a lot more choices both in barrels and production ammo.  That is about the only thing you said that isn't bs!  But think about it, the 300 Blackout/Whisper/Fireball has been out for 30 years while the 300 HAM'R has only been around for a couple of years.
The 300 Ham'r is just a revamped 7.62 X 40 wt    Let's see, you look at a cartridge and then improve on its performance, isn't that the object of the game?  The 7.62x40WT (which also out performed the BO in supersonic loads) was a good cartridge, and the 300 HAM'R is even better.
The real difference in the terminal effects will almost be negligible in barrels under 12 inches and even in the longer barrels does 150fps really make much of a difference  If nothing else, go back to school, your math is awful!  Besides, you want to call the 300 HAM'R a "niche" cartridge but then you want to use data for just 12" and under barrels?  Talk about a niche!
Most people don't run their reloads at max pressures anyways as I download my 110gr black tips around 100fps off of max load and I don't see much of any difference in capability in its terminal ballistics. The simple fact is there is very little difference between the two when it comes to supersonic but huge differences between the two when it comes to current and future availability of products. As the 300 Ham'r is a very niche round where it has a small advantage in supersonic speeds over the 300BLK and no advantage in subs. The 300 Ham'r lacking in power to other rounds that can fit in .223 mags and bolts that don't do subsonic.  Translation: "I have no factual data so I'll throw this out there and try to get someone to believe me!"
It is obvious, you have never shot a 300 HAM'R, much less have you done any type of testing on one.  I have had both as well as a 7.62x40WT and I have done a good bit of testing on all of them.  Facts don't lie.  If all you want to do is to shoot subsonic, get a Blackout.  That is what the cartridge was designed for!  Could that be the reason J.D. called it the "Whisper?"  If you want the best choice to shoot supersonic you can't beat the 300 HAM'R.
Sorry for being a little long winded.  I just get irritated when someone gets on a thread trying to tear something down, yet they have no clue of what they are talking about.
To quote Fletcher in the outlaw Josey Wales; " Don't piss down my back and tell me it's raining."

I took a look at the 2021 Sig catalog today, and noticed 300 HAM'R ammo.  It would be nice if they also offered a 16" 300 HAM'R caliber exchange kit for the Sig MCX Virtus.

SBR also has ammo available too

I don't have any particular beef with 300Ham'r.  I think it is a fine cartridge, but I also think it spends too much time punching down. I think it's biggest competition is 6.8 spc, 350 Legend, and 7.62x39, especially in the AR platform.  And maybe it can steal some .308 thunder as well.  

I do believe the numbers shown above 100%, but I also know that everyone here is well aware of the fact that .300blk sucks with heavy (non-sub) rounds.   The most popular rounds are in the 110-125 range.

The best round IMO is actually the Wilson loading of the 110gr Tac-tx (2400 fps).  I see Wilson also load one the many 110gr Varmint rounds (2350 fps for 110gr V-max, although Hornady Black lists it 2375).  Throw in the Fiocchi loaded 125gr SST (2200) and maybe the Lehigh 115gr Controlled Chaos (2325) and that is a big chunk of the best .300blk rounds.  

Even with these "good" rounds, I know that 7.62x39 is still more powerful than 7.62x35, and I would suspect 7.62x41 to follow the same trend.  But when dealing with barrels in the single digit range, we might be looking at different needs for different people.  As someone who cannot shoot suppressed, things like flash, gas, blast, recoil, and function all play a part in the equation, at least for me.   A thread like this came up awhile ago, and I had asked the same thing about how does it function out of a short barrel, because that is .300blks bread and butter.  I also read though the Texas Hunting link, which answered some of my questions.
With all that said, it still looks like an interesting round, especially when you around that 1 foot mark and above.  Seems great for hunters using 130gr ammo.

I use 125gr  bullets and CFE blk in my ham’r,  2500fps is easy to obtain and not maxed out. I tried lil-gun in my ham’r and it was scary fast but port pressure (or lack there of without crazy chamber pressure spikes)was an issue. The powder is just plain scary to work with, very unpredictable and I’ve heard it is tough on barrel throats, the way it heats a barrel I can believe it. My pet CFE  load runs 2400+ out of my 2 16” rifles and around 2500 out of my 18”, this load is VERY accurate.  Look , the aac is an over grown pistol cartridge and the ham’r is a legit  service/hunting  cartridge, is it a .308 Winchester, no, is it more accurate, reliable and slightly more powerful than a 7.62x39, yup. Can it shoot all the great .308  bullets out there in the 100-150gr class and still expand, yup for the most part. Is it a sub-sonic wizard of a cartridge absolutely not. I say the aac and ham’r both have their place. It better to just own both, lol.

Seems you have very little knowledge on the 300BLK as it is not the 300 Whisper. The 300 Whisper was designed from 221 fireball case and was made for subsonic. The 300BLK on the other hand was designed to be supersonic and made from the .223 case.

I am also not tearing anything down. It is when people sit there and say the 300BLK will bounce off a person that is wearing thick clothing while the 300 Ham'r will tear them in half I call B.S.. There is very little difference between in the supersonic capability these cartridges. Any animal that can be humanely killed with the 300 Ham'r can be done with the 300BLK. Many have already tried what the 300 Ham'r is doing and if it had been pushed by anyone else other than Bill Wilson it would be relegated to the same heap of all the others like the 7.62 X 40 WT. There is just very little advantage to the 300 Ham'r that isn't solved by going to another round that can do what it is trying to do but better.

What exactly are the improvements of the 300 Ham'r or should we just call it what it is the 7.62 X 41 wt over the 7.62 X 40 wt? The extra 1mm? The 7.62 X 40 wt came out before the 300BLK and it wasn't a success what do you think adding 1mm and pushing the neck back slightly will do? As I said people are into niche cartridges just like the 30 Herret, 30 HRT, 30 RAR, TAC 30, 7.62 X 40wt, 30 Sabertooth, 300 OSSM, 30 American. All of which were faster than the 300BLK but all of which most have never even heard of.

I also get a little annoyed that people like you say things like if you want to shoot subs then go with the 300BLk. When in actuality it should be if you want a rifle that will have the same terminal effect on the game it is supposed to be used for as the 300 Ham'r and have the capability to shoot quiet subs, more choices in barrels, more choices in ammo, more choices in where you can get that ammo all while being cheaper, then the 300BLK is for you.

What is the cheapest Ham'r barrel? The 300BLK has many manufactures making many sizes and shapes of barrels. Good quality from barrels from Faxon, CMMG, Odin, Ballistics Advantage, etc go for between $129 and $169. The cheapest barrel I found from the only manufacture that makes them is $229 with most costing $249. What is the cheapest Hamm'r ammo? The 300BLK has steel case ammo being made for it so I don't ever see the ammo price for the 300 Ham'r being less than 300BLK. When the craziness stops where will you be able to buy 300 Ham'r ammo from? I can go to walmart and pick up a couple varieties of both supper and sub for 300BLK. You will be lucky if Bass Pro ever stocks 300 Ham'r. Even if you are reloading the brass will be cheaper and easier to find. It will also be easier to make as there are many cutting dies/tools and setups made specifically to make 300BLK .

I do know how a ballistics chart works. But when you are comparing a round that is not being made by other companies that do their own independent testing and find that pushing it to the limits is not what they like to do and therefore when looking at ballitics charts all things tend to be equal. For example most ballitics charts have the 300BLK running anywhere from 100 to 150 fps slower than what reloaders can push them too. So, when and if the 300 Ham'r ever makes it onto a ballistics chart with say hornady making the ammo then we can have a true comparison.

Who told you Lil Gun gives you unpredictable big pressure spikes? It is a very common powder used by a couple hundreds of a magnitude more people than the 300 Ham'r and this is the first I have heard of pressure spike let alone trying to use them to justify higher FPS. With the 300BLK the only time with any powder you will get a pressure spike is if you don't use enough in subsonics and that is what you may be thinking of.

I am sorry you only think the 300blk is good for quiet subs. I am sure all those tens of thousands of pigs, deer and every other mid size game taken by supersonic 300BLK might disagree. Then again considering that the supersonic 300BLK is very similar to the 300 Ham'r which can't do subs. What does that make the 300 Ham'r good for?

It is you who have little knowledge on this subject.  The 300 Blackout is in fact the commercial equivalent of the 300 Whisper.  The only difference is the the 300 Blackout was submitted to SAAMI with some minor dimensional changes to avoid a lawsuit.  You don't think 300 fps is a significant improvement over a cartridge that runs in the low 2k's, with no more difficulty in forming brass?  Perhaps you can get a Blackout barrel cheaper than a HAM'R barrel, but cheaper doesn't necessarily mean better.  

For not wanting to start a pissing contests you sure are doing a lot of pissing.

Now you are saying that besides being able to take elephants at 3,000 yards while the 300BLK will not penetrate a thick piece of target paper you are trying to say that the 300 Ham'r is more accurate? You do know that they can use the exact same bullets right (except for heavy subs because 300 Ham'r just doesn't do that)? Can you please explain how over stabilization of a bullet affects accuracy at 100 yards. Last I checked when you over stabilize a bullet it starts to affect accuracy at ranges of 300 yards and beyond due to the keeping the bullets nose high. Then again your antidotal evidence of one is overwhelming so I must concede that your barrel is a laser precision instrument capable of bringing down shuttles orbiting the earth. Because no other barrel manufacture knows how to make a precision barrel for the 300BLK but as you hinted too most are work horses that go out into the field and worry less about what they can print on paper and more about the capability of short barrels throwing lead faster and harder than most other SBRs without a big fireball coming out the end.

I know a lot about the 300BLK. Are you saying what I was telling you wasn't true? Because it seems you know very little about the cartridge other than a dislike about it. JD is that you?

The 300 whisper made by JD jones was made for subsonics by using a stretch out version of the .221 fireball case where the neck was to thin to get many uses out of higher pressure supersonic rounds. The 300BLK did its cues from it just like the 7.62 X 40 and the 300 Ham'r took their cues from other cartridges that were very similar. The 300BLK was specifically tested and made for supersonics at the behest of the military all the while being made from the .223 case with a chamber to accommodate a thicker neck. This is why you don't want to put 300 blackout ammo in the 300 whispers as they were not made for the same case dimensions.

BTW you can also get more expensive 300BLK barrels that cost twice as much as the Ham'r barrels so are those barrels better just because they cost more? Now here is the really hard one that will blow your mind you can even get the same Wilson barrel in 300BLK but with more varieties and lengths available for the same cost. But you can't get less expensive barrels for the 300 Ham'r and are you calling Ballistics Advantage, CMMG, Ogdin, Faxom bad barrels?

Plus if it isn't any more difficult to form the brass please show me the carbide cutting dies that I can use on my Dillon to form 300 Ham'r brass. For the 300BLK there are at least 3 manufactures making carbide cutting dies for it along with others who make non carbide cutting dies for those who want a cheaper alternative and don't do thousands of pieces.

A chamber cut to handle bullet weights of 110gr to 220gr has accepted more compromises than a chamber cut to prefer 125gr to 150gr bullets. I do not doubt that generic Hamr barrels would out perform Blackout barrels.
DB

Bingo, you nailed it, one of the two reasons the BLK can't inherently be a super accurate cartridge with supersonic bullets, the throat has to be so long to allow the long subsonic bullets to chamber. The HAMR throat spec allows many of the suitable bullets to be just off the lands. The other I've already mentioned, the twist is way too fast for optimal accuracy with 110-150gr bullets. Here's a "clue" about this, benchrest shooters choose the slowest twist rate that will stabilize their chosen projectile.

Before I settled on the 1-15 twist for the HAMR, I spent days and days on the range shooting close to 1000rds testing twist rates of 1-11, 1-11.25, 1-12, 1-13, 1-14 and 1-15 to find out the optimal twist for applicable bullets in the 125-135gr range. While all would shoot into 1", the 1-15 will shoot shoot under 3/4" with loads it likes. The 1-13 is the optimal twist for 150gr bullets, just like it is in a .308

Basically the BLK is a cartridge of compromise in order to shoot bullets ranging from 110gr-240gr while the HAMR is optimized for 125-135gr bullets while still performing well with a weight range from 95-150gr. I have no beef with the BLK, heck it's our 3rd best selling caliber after 5.56 and 6.5CM, it just doesn't fit my personal need. When I shoot subs I choose a 9mm.

I'm not JD, but he is a good friend that's been there and done that!

Actually I do have a little history with the BLK, Robert Silvers called me early on in the project and sent me ammo for testing, which I did on TX hogs. At that time I was heavy into the 6.8SPC since that was the first non-5.56 cartridge we mfg barrels for and build guns in. I've killed more hogs with the 6.8 than any other cartridge other than the HAMR and it has pretty good terminal performance, just not as good as the HAMR. However I was not at all impressed with the terminal performance of the BLK on hogs, yes it will kill them (heck I've killed them with a .17HMR with a shot behind the ear) but no where close to as reliably and efficiently as the 6.8 or HAMR.

BTY, since you "know a lot about the 300BLK", exactly how many game animals have you killed with it and at what ranges?

who told me?..The internet with my verification.

it gives pressure spikes when trying to get to 150fps of the posted Hamr velocity.  I can open that gap back up using lil gun in the Hamr.  "it's only 150fps slower is not correct.

BTW I got my Hamr barrel for $150