Wilson Combat .300 HAM'R

On Wilson Combat’s Facebook feed today they have announced the release of the “.300 HAM’R”. This looks like the same idea as their .458 HAM’R, which is that it is an improved version of another cartridge - in this case the .300 Blackout. Wilson is a little cryptic with the relevant dimensional / structural details, but their main claim is that the cartridge has velocity and energy that is around 200 to 300 better than .300 Blackout across equivalent grain weights. The rifles they build for this caliber are the same .30 cal AR’s they have done for a while - meaning $2,500 to $3,500 price range. The brass is custom headstamped WC 300 HAM’R. I presume the pressure scenario is the same as their .458 HAM’R, meaning that one can safely fire .300 Blackout and .300 HAM’R in a .300 HAM’R chambered rifle, but should not fire the .300 HAM’R ammo in .300 BLK chambered rifles.

When I look at their 125gr load in this caliber (or any load in this caliber), I am wondering why anyone would want it when they can just purchase an AR chambered in 7.62x39 for around $700,and which has ballistics, performance, and handling about the same (couple hundred fps difference) as this new load. The one advantage I suppose would be projectile availability for the .300 HAM’R since there are countless more .308 projectile options available as compared to 7.62x39. Other than that… meh…




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I received some .300 HAM’R today and found that the case is completely different than the .300 Blackout, so it’s a new custom caliber above & beyond the sort of thing they did with .458 HAM’R (a .458 SOCOM improved). I’m not sure why Wilson Combat didn’t make this clear in any publicity photos or literature anywhere. They also didn’t answer any of my questions about the case size or compatibility with Blackout when I asked them via Facebook. They certainly did a ton of promoting online through the blogs, and on Facebook, etc… There are likely other writers and people online who will post about this and show the difference. In the photo below there is a 300 Blackout on the left, the HAM’R is in the middle, and a 6.8x45 Kramer is on the right for comparison.


So, can it be made from reformed 5.56 brass? Will it feed through standard AR 5.56 mags? Is there nothing besides a barrel change needed to go from 5.56 to Ham’r? If any answers are NO, I’ll stick with BLK.

The .300 HAM’R looks about 7.62x 42 or 43…like a.222Rem case neck-expanded to .30 cal…
Just a bit different from the Nasional Polisi 7.65x45 Indonesian by Pindad for their M4 clone Police rifles several years ago.
Old wine in new bottles…nothing really new…
Would like to see comparative trials though…but a Pindad might be hard to get…
Doc AV.

Here is a lineup of similarly sized cartridges to the .300 HAM’R to better compare to other rds that are in it’s class.


  1. 6.5 Grendel
  2. .300 Blackout
  3. 6.8x45 Kramer
  4. .223
  5. .22 Nosler
  6. .300 HAM’R
  7. 25-45 Sharps
  8. .224 Valkyrie
  9. .222 Remington
  10. .222 Rem Mag
  11. 7.62x39
  12. 6.8 SPC

Also, here is an interview with the man himself - Bill Wilson, going over all of the finer points of the .300 HAM’R:

At the 5:30 mark he explains how there was some considerable trepidation and push-back from his management (who work for him) about engaging in this project. Who could blame them after the 7.62x40 WT which never took off.

Has anyone compared the case demensions between this & 7.62x40 WT? Just curious as they look nearly identical, maybe they are just rebranding the 7.62x40 after it flopped as other manufacturers have.

As far as being able to fire 300 blk from a 7.62 hammer rifle looks like you would have a serious headspace issue.


I’m quite sure now that there is no compatibility between the blackout and the HAM’R, I was just speculating at first that there might be before I saw them next to each other. I will compare a 7.62x40 to a .300 HAM’R tomorrow at work.

You appear to have nailed it with the 7.62x40 WT comparison. They are almost identical, but have slightly different case lengths and shoulder locations (just enough to squeak a new caliber designation through SAAMI that isn’t 40 WT?). I don’t know about the pressure situation exactly, but presuming that the 40 WT is lower pressure, then it appears like one would be able to easily shoot the 40 WT in a .300 HAM’R gun, and the brass should neatly fire-form itself into reloadable .300 HAM’R. That being said, the 40 WT cases were just resized 5.56 brass, and the .300 HAM’R is purpose-built by Starline or whomever, and so the case wall or web thickness could have something different going on - who knows?

The case length on the .300 HAM’R is 40.35mm, while the 40 WT is 39.65mm. Below, the HAM’R is on the right, and the 40 WT is on the left. Either caliber can have a few mm of play on the projectile length also, and the HAM’R is showing one of it’s shorter options with the 130gr HP


Gotcha, good work there bud. I think they’re just pulling a 6mm Remington / 244 on the modern tacticool crowd. Can’t operate operationally without some sort of super duper operator name tacked on the back of your ammunition these days, ya know.

Yeah, also they could make “HAM’R” into an entire line of cartridges possibly. More convenient to say, print, and promote than “Wilson Tactical”. They already have 2 flavors. Also, out of curiosity I scoured the internet with some searches, and The Gun Collective appears to be the first who brought to light that the HAM’R is a revamp of the 7.62x40 WT, as mentioned here at the 1:41 mark:

I wonder where they got the info from as Wilson Combat seems to not be pointing out this relationship at all. Maybe he had some cartridges earlier than most? From the get go, I was stuck on the notion of it being an improved Blackout, in the same way that their .458 HAM’R was vs SOCOM and didn’t consider that they would try anything with the WT, which I thought was all but dead. It makes some degree of sense in hind-sight now though.

I called Wilson Combat, as I just got in some 300 Ham’r to retail.
I was told there is a size difference in the 300 HAM’R vs. the 7.62x40mm Wilson Tactical.
The 300 HAM’R has a longer case length by 40/1000" and the shoulder starts 40/1000" longer down the case.
This increases the powder charge by 2.1 more grams. ( I measured it and they are correct.)
They also said that the two cartridges are not interchangeable.
I can see you would not be able to shoot the 300 HAM’Rr in the 7.62x40WT chamber.
You may be able to the 7.62x40 in the 300 HAM’R Chamber, but it is not a good idea, as it is shorter and you may get gas leakage and chamber damage.
Like any firearm, it is a good idea to shoot what the barrel reads.
I’ll stay with my 300 Blackout ;-)

Below picture on the right in black: on left .300 HAM’R vs. Right 7.62x40WT

Starline is now producing brass for this caliber. Not sure if Starline was making the original cases for Wilson as I notice the zeros look more square on the Starline version. At first I presumed that they must be the original maker of the brass, since why else on Earth would they get into such an obscure offering that only exists in pricey W.C. uppers / firearms.


I’ve been an avid fan of the 7.62x40 since Kurt Burchet developed the cartridge (around 2008 as I recall). The 7.62x40 out-performs the .300 BLK with supersonic ammo by a WIDE margin. As I have no interest in shooting heavy subsonic bullets from an AR/MSR platform rifle, the .300 BLK offers nothing to me.

When Wilson became interested in the “X40”, he made a deal with Kurt to market it with the “WT” suffix added. Wilson supposedly changed the headspace on his WT version by 0.003 inches (0.0762 mm) to make it “better” than Kurt’s original design.

The X40 is easily made with cut-down 5.56x45mm or .223 Rem brass and formed in one step. I’ve also formed 1,000s of cases using once fired 5.56mm blanks. It uses all standard AR/MSR parts except the barrel; it operates at the same pressure limit as 5.56x45mm. With 110gr bullets, I safely get 2,700 fps from a 16-inch 1:12 twist barrel; an 18-inch barrel gives a little more muzzle velocity. The same barrels launch 125gr hunting bullets at 2,450 and 2,500 fps respectively. All this is with sub-MOA accuracy. One note: for reliable full-magazine capacity functioning, modified magazines with reduced internal forward ribs are required. The new .300 BLK family of magazines from MagPul, Lancer, and others work perfectly - and are also required for the .300 Ham’r.

The .300 Ham’r is a SLIGHTY modified X40 which was specifically designed and optimized for one bullet, the 130gr Speer HotCore. Wilson lengthened the case approximately 1mm and moved the shoulder forward so that when seated to maximum STANAG magazine length, the 130gr Speer crimps in the cannelure. In addition, Wilson slowed the barrel twist to 1:15 reducing chamber pressure slightly, allowing for maximum powder charges without over-pressure.

Starline is and was Wilson’s original brass supplier for the .300 Ham’r.

Much more information about the 7.62x40 and comparisons to the .300 Ham’r can be found on the MSREvolution forum, especially here and here.