.300 Ham’r

[Rick R]

My wife came home with a new stripped AR lower and said she wanted something “different” built on it. My reply was “Yes ma’am!”. After a bit of research we’ve decided on Wilson’s .300Ham’r as it is alleged to approach 30-30 ballistics without drama or too many non-standard bits or pieces.

Has anyone here had any luck with cast in this fairly new cartridge? Seems like a 130-150ish grain boolit might be a lot of fun.

[Burnt Fingers]

Look at some data before jumping in.

300 Hamm'r
300 Blackout
7.62x39

All three are very close with a 150 gr bullet.

Two of them you can make your own brass from 223.
Two of them you could normally find ammo just about anywhere.
One of them is pretty much in niche status.

Personally....I go with one of the bottom two and I have. I have 10.5" AR pistols in both 300 Blackout and 7.62x39. I also have one in 350 Legend that's a real hoot to shoot.

[Rick R]

Look at some data before jumping in.

We did and I already have two .300Blk guns.

Wilson recently had the Ham’r listed by SAAMI so now any company can make guns and ammo. Starline makes brass with the proper headstamp.

You can’t inadvertently chamber Ham’r in a 5.56 gun and blow yourself up. You can with .300blk super sonic loads.

The Ham’r allegedly is 2-300 fps faster than the Blk or .30Ruskie and 150gr jacketed.

[Burnt Fingers]

We did and I already have two .300Blk guns.

Wilson recently had the Ham’r listed by SAAMI so now any company can make guns and ammo. Starline makes brass with the proper headstamp.

You can’t inadvertently chamber Ham’r in a 5.56 gun and blow yourself up. You can with .300blk super sonic loads.

The Ham’r allegedly is 2-300 fps faster than the Blk or .30Ruskie and 150gr jacketed.

Load data doesn't support that.

[farmbif]

I want a HAM'R too but would much rather have the a wife that wants one.
you are one lucky man

[c0wb0y84]

Load data doesn't support that.

Sure it does. Take factory load data for blackout and custom load data for the ham’r...

I say build it in the ham’r. Yes it’s niche but it will be fun. Making brass is easy and buying it even easier.

I don’t know if anyone that’s reported success with casting but that may be due to the boolit/powder limitations.

[single shot jimmy]

I'm tempted by 350 legend. Really don't need it though.

[yovinny]

Might want to do some browsing at 300blktalk for some first hand experience.
I was hot for the ham'r, untill I saw most were only getting the 200fps velocity increase advertised with the lighter 110-125gr bullets. Actual velocity increase over the 300BO with heavier bullets seem more along the lines of 100-150fps and hardly seemed worthwhile starting with another new caliber to me...

[Rick R]

I'm tempted by 350 legend. Really don't need it though.

I ran into a friend the other day I hadn’t seen in a few years. We were talking guns and he said he’d bought a .350 Legend. He said it slays deer but the recoil is almost nonexistent.

[c0wb0y84]

Might want to do some browsing at 300blktalk for some first hand experience.
I was hot for the ham'r, untill I saw most were only getting the 200fps velocity increase advertised with the lighter 110-125gr bullets. Actual velocity increase over the 300BO with heavier bullets seem more along the lines of 100-150fps and hardly seemed worthwhile starting with another new caliber to me...

It was designed around pushing the lighter .308 Boolits faster than the 300. It’s not a versatile round nor was it meant to be. It was designed to be a hunting round that resembled 30-30 power in an AR. 110-135 gr j-words are its ideal projectile.

Heavies are not going to do well bc they weren’t meant to do well. It’s predecessor the 7.62x40 WT has a few more projectile options but is still limited by COAL to fit in an AR mag.

It has limitations but they don’t make it any less fun.

[yovinny]

It was designed around pushing the lighter .308 Boolits faster than the 300. It’s not a versatile round nor was it meant to be. It was designed to be a hunting round that resembled 30-30 power in an AR. 110-135 gr j-words are its ideal projectile.

Heavies are not going to do well bc they weren’t meant to do well. It’s predecessor the 7.62x40 WT has a few more projectile options but is still limited by COAL to fit in an AR mag.

It has limitations but they don’t make it any less fun.

Maybe you should reread your first post then..
The one you now contradict while quoting me....��

[c0wb0y84]

Maybe you should reread your first post then..
The one you now contradict while quoting me....��

I’m confused about a contradiction unless you’re referring to my tongue-in-cheek comment where I was poking fun at the ham’r. In that case I was goofing about inflated claims of horsepower that all companies push when they come out with something new.

My quoting you was in support of the faster velocities with lighter Boolits and lower performance with the heavies.

[yovinny]

Then I misunderstood,, my apologies..

[Texas by God]

The easy button would be 7.62x39. Cheaper dies, ammo everywhere normally, if loaded to the same pressure as the Wilson, it would be the champ due to more ( slight) powder capacity. The 10” twist is cast friendly but the ham’r may be better with it’s slower twist. My .300 BO is my “.30 Carbine +P”; my .30-30 is my “.300 BO +P”.
Let us know what you go with, we like pics.....

[John McCorkle]

The easy button would be 7.62x39. Cheaper dies, ammo everywhere normally, if loaded to the same pressure as the Wilson, it would be the champ due to more ( slight) powder capacity. The 10” twist is cast friendly but the ham’r may be better with it’s slower twist. My .300 BO is my “.30 Carbine +P”; my .30-30 is my “.300 BO +P”.
Let us know what you go with, we like pics.....

Ha, 300 BO+p I like it

Sent from my moto g(7) power using Tapatalk

[popper]

Other than more powder space, the difference between BO & Hamr is in the throat. Per chamber spec, both have 0.17 taper to bore (309 to 300),
BO has 0.17 309 freebore vs 0.08 hamr. BO neck is 0.04 longer.
From both my BO barrels, the freebore appears to be almost 0.3 then a taper to 0.3 bore. Conclude that Hamr bullets need an ogive starting close to case mouth. Ergo, many cast bullets won't fit! You get 0.25 more powder space. Can it be used? In a 20" barrel, probably. May not get 100% powder burn in shorter barrels depending on powder speed. I'll make a Hamr case for GRT and check what works.
Basically it's like the 40WT, tuned to light jacketed stuff so casters may not get all they desire. For some it may get desired performance, others not so much. I tend to use 140-150 gr cast - will it really work? For my 170? Probably not.


From GRT, 110 vmax 21gr cfeblack 2300 fps 20" barrel incomplete burn
150 Lee 21gr cfeblack 1800 fps 20" barrel, complete burn. RL7 is too slow!
16 " carbine is incomplete burn for sure (~70%).
I've cronyd my 145gr cast in 18" barrel - 2100 fps, H110. It's a 1;10 twist. I'd go 1:12 for Hamr.

[c0wb0y84]

The 40WT may be a better option bc they can use a (marginally) wider range of bullets and the difference in performance between it and the ham’r is minimal. I’m not really convinced that cast is the way to go with those two rounds. Projectile length is gonna be the limiting factor more so than weight.

Might have luck with powder coat and gas check.

[Lloyd Smale]

well i dont have much accuracy reporting yet because its winter. I know I shot the 130 rcbs spitzer gas check (my hands down favorite cast bullet for accuracy in the 30s) cast at 18bhn and pc coated with a full power charge of cfe-blk which should be pushing it around 2300+ out of my 18 inch barrel. All i did so far is rough sight it in. I shot it off the hood of my jeep with no rest of any kind at 75 yards and the final 3 shots after zero went into just under an inch. Why it instead of a 762x39? I had one and it didnt feed for crap with anything but 10 round mags. this one feeds great with any 300 black out mag. It will meet or beat anything a 762x39 can. Brass can be made from 556. try finding brass 762x39 brass on the ground at the range or even on here. Ive killed deer with the 300 blackout out to 200 yards and it did suprisingly well. this round adds an honest 200-300 fps on to what the bo will do so think of it as improving on it probably more then a 300 win mag improves on an 06. Probably a closer comparison would be the added power of a 300 win mag over a 308. Where my 300 bos pushed a 110 to 2250 fps the ham'r pushes a 130 to 2400 and with some loads closing on 2500. Those loads put it above the 762x39 and the 6.8 and are crowding my favorite ar, my 6.5 grendel.

Bottom line is the hamr is probably better at 200 and under and the grendel the better choice out past 200. But id sure not hesitate to take a whitetail at 250 yards with the ham'r. Some of us have been doing the ham'r for a long time. Its called loading your 3030 with 130 spitzers and hunting with one in the chamber and one in the mag. i shot a couple deer with dads old marlin 22 inch cdl 3030 at over 200 yards. My buddy actually shot a 4x4 muley out west with a similar set up at 310 yards (measured with his range finder) and dropped it in its tracks. Only down side so far to the ham'r ive found is the 110 and 120 tssx that work so well in the bo wont work in the ham'r. to fit in a mag with that long slender nose they have to be seated to deep to work. Made me scratch my head because wilson had data for them. My guess is he must of just pulled that out of his ! Sure wish that 110 would work. Im not a fan of barnes bullets but that is HANDS DOWN the best bo deer bullet. Like i said my range time has been limited and ive yet to kill something with it. But how could a 300 bo magnum not be a good round???? I could care less about versatility. Ive got 3 ar15s in 300 bo and a ruger american. Only one of them i bother with sub sonic is the american. there to dirty for ars. 200 rounds and your gun looks like you dipped it in dirty grease. Plus in the american i can shoot my favorite 130 rcbs with a little bit of unique or bullseye sub sonic all day long and do it for less money and using half the lead. i doubt id ever shoot another subsonic load through my 300 bo ar15s.

As to what it will feed. My wilson barrel has ran perfectly with 130 speer hps, 130 bts, 130 hot cores,130 ww power points, 130 pro hunters, 130 interlocks, 150 interlocks and 150 pro hunters. Now that said ive shot two 5 round mags of each of them not 500. What didnt work were the 110 barnes the 120 barnes and the 150 horn sst. It ran 150 bts too but they had to be seated a bit to deep and i got flattened primers with the same loads as i did with the other 150s. Nothing fancy. All bullets with crimp groves were seated right at the crimp grove. The ones without a crimp grove were all seated to the same place as the 130 interlock. The 130 rcbs cast ran perfectly too. I probably shot a total of a 150 of them so far and it hasnt missed a beat. So dont buy into the fact this round is picky for bullets. Theres a ton of bullets that work just fine. Right now im hoping the 130 interlock or the 130 speer hp shoot well because i have a bunch of both. Ive shot many deer with that 130 speer hp out of my kimber 308 and it knocks the cork out of them. Probably a bit to explosive and id bet it would work perfect in the ham'r.

[Old School Big Bore]

I don't own a BO or a Ham'r (yet!) but I agree with the spitzers in .30-30s, and it sounds like the Ham'r might be my next upper. I've been using the Sierra 125 spitzer in a Savage 340 since I found out that it's got the same construction (varmint) as Sierra's other .30-30 deer bullets. It fits in the 340 magazine, I get 2400 f/s out of it, and it's worked fine on our smallish whitetails as well as javelina, coyotes and even hogs.
I've decided to get rid of my 18" .450 BM upper and get a cast-friendly bolt 450 instead, so I'll have a vacant lower in search of an upper. As far as .350 Legend goes, my son has a Model Seven so chambered, and I think if I build one it'll be a bolt gun too. A manual action is just easier to deal with, when you like to load the whole range of levels each caliber is capable of, than trying to get an autoloader to run. I'm not slamming autos, I have several and warm 'em up frequently, it's just that their performance window is narrower than I like for general shooting. I tend to stick with just a go-to J-word load for my semis and use manuals for playing around with different weights/speeds.
Ed <><

[Rick R]

Well my wife and I got her new lower assembled yesterday and I got a shipping notice from Wilson on the barrel and dies. I plan on trying jacketed loads first, then possibly straying off into cast boolit loads.