7mm Mauser out of an AR-15 ?

[Wolfdog91]

Neat ! Just love all the stuff you can do with AR-15's :-D

https://youtu.be/llAURDuFG1Y?si=m6gfO9tuQm0OQ3aw

[Kosh75287]

It looks like someone went to the trouble to re-invent the .280 British intermediate round, developed for the "bull-pup" EM-2 platform, but for use in the AR-15 platform. Not really a BAD thing, I guess, though magazine capacity will suffer.
I'M wondering if anyone will rechamber an IMI Tavor for this round. Putting this round in a "bull-pup" platform would pretty much make the "re-invention" circle complete.

[Larry Gibson]

Appeared to be a couple hundred +++ if not 300 +++ fps short of 7x57 Mauser cartridge capability and that's with the light weigh 119 gr bullets used. Doubt the cartridge would be that impressive with 139 - 175 gr bullets. Certainly, wouldn't come close to the 7x57s capability.

[376Steyr]

I was wondering how you fit a 7x57 into a AR-15 platform. Turns out it is a 7mm Valkyrie, which is the "equivalent."

[36g]

There was a shortened 7mm Mauser cartridge developed in the 1950s or 1960s that basically took a 7mm Mauser and shortened the brass. I've got some boxes here somewhere. I don't recall what firearm they were intended for though.

[Wolfdog91]

Appeared to be a couple hundred +++ if not 300 +++ fps short of 7x57 Mauser cartridge capability and that's with the light weigh 119 gr bullets used. Doubt the cartridge would be that impressive with 139 - 175 gr bullets. Certainly, wouldn't come close to the 7x57s capability.He was shooting up to 2966fps on a few of those loads
Same weight range bullets horn days book shows it topping out a 2800 and again these are test loads . No to mention Ed is a speed demon and likes to run as fast as possible with the help of all copper bullets so I can guarantee he's going to be running these much faster
https://uploads.tapatalk-cdn.com/20240114/2b8eeb4ee771097f5ad9afbcc4f4536b.jpghttps://uploads.tapatalk-cdn.com/20240114/b57e2d83b626087b9acb545a5630fa7f.jpghttps://uploads.tapatalk-cdn.com/20240114/6c342ace9d09d4abb5c426a6b300e293.jpg
https://uploads.tapatalk-cdn.com/20240114/a4981961bb3920086678201e1d46de29.jpg

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[Kestrel4k]

How is this a "7mm Mauser in an AR-15" ??

I guess the subsonic 158gr handloads in my .350 Remington Magnum would be "38 Special out of a Remington 660" then.

[Fitz]

Something about a Modern Black Rifle the OLD Timers just can't see anything good with them , And on the other side of the spectrum the Youngsters can't see anything good about beautiful Walnut and Dark blue curvy lines .

I just like them all the old battle axes right up with the new wildcats ,, which the modern sporting rifle has allowed more wildcats than any other type rifle from what I can see with the CNC machining they are logo guns we can all have fun with.

[Texas by God]

I like AR15s.
But their action and magazine size relegate the cartridges that FIT them to ALMOST status.
Every new cartridge is ALMOST a corresponding “old cartridge”
My 6.8 SPC is ALMOST a .250 Savage.
The .30 HAMR is ALMOST a 30-30 Winchester.
The .350 Legend is ALMOST a .35 Remington.
If you load the old cartridges (in strong actions) to the same pressure level as the new AR rounds- the difference gets much wider.


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[Wolfdog91]

I like AR15s.
But their action and magazine size relegate the cartridges that FIT them to ALMOST status.
Every new cartridge is ALMOST a corresponding “old cartridge”
My 6.8 SPC is ALMOST a .250 Savage.
The .30 HAMR is ALMOST a 30-30 Winchester.
The .350 Legend is ALMOST a .35 Remington.
If you load the old cartridges (in strong actions) to the same pressure level as the new AR rounds- the difference gets much wider.


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It's a give and take.
With AR-15's if you have two brain cells and a vises you can build them yourself without much problems, don't need to drive and wait and pay a gun Smith for barrel changes and all that good news . Order the barrel and the bolt and it's leggo builder time. You can actually adjust them to fit pretty easy and when you a small person like me at 5'1" fit is really important. You don't need a lathe , milling machines and all this other stuff. No to mention I can do the whole one lower multiple uppers deal. Heck even further I can only have a few BCG's .
No to mention most of these AR based wild cats work off of brass you can pretty easily and affordably get that ranges from range pick up all the way premium Lapua or Peterson.

All of that and I have to give up some pretty wood and a small disadvantage which let's be honest here 80% of shooters really don't need a top high throttle performance out of most. You you don't like AR's and already have the legacy cartridges these are performing similar too then it's just kinda a non starter for you to even bee looking at these as much past a novelty. If your a 100% "a gun is a tool I only have guns that fill a purpose" type of person then yeah these are again non starters. Now if you like me however who has the whole "need" bases covered 15 ways to Friday and jus tlile playing around with stuff but don't wan to go full out $1500-$4000 custom bolt guns made off of legacy cartridge deal....welp these are a extremely viable option

[MostlyLeverGuns]

Brunettes, blondes and redheads, bosoms, butts, long legs, we all have our preferences. Since I was 12(1961) I thought the Model 70 handled like a 2x6 with a pipe stuck to it while a featherweight Savage 99 handles wonderfully. I do have a couple AR-15s, even a Side-bolt 6.5 Grendel, we practice with them every couple months as our 'zombie' guns, same with the plastic pistols in 9mm, light and lots of bullets for carry, but a 1911 or a single action 45 Colt are just more fun. In tough conditions the stainless and polymer stuff does fare better, still hunt with those walnut and blued 99's. But that's just me, I don't judge you, some might think I must be be dumb, OH WELL.

[rockrat]

Almost sounds like close to a 7mm BR.

[Larry Gibson]

Wolfdog91

We see the "almost as good as" play on words all the time when comparing a smaller cartridge to a larger case of the same caliber. The fact is, the smaller case will never equal the velocity of the larger case with a given bullet when both are loaded to the same pressure in barrels with the same effective barrel length [the length of the bore minus the chamber length]. Case capacity, all other things being equal, matters....that's a fact.

As to your selected load data, that particular Hornady manual is holding the psi level down at the SAAMI MAP of 46,000 CUP or less. I suspect the 7mm in the AR was pushing 50,000+ CUP or 60,000 psi +/-. Here is the data from an older Hornady manual showing loads in a 22" Ruger M77 which had an effective barrel length of 19.5". The AR in the video had a 24" barrel with a probable 22.25" +/- effective barrel length. The Hornady data below was developed to a CUP level of 50,000. Note the velocities of 3000 and 3100 fps+. I have duplicated several of those loads and pressure tested them in my 22" barreled M95. The psi measured was in the 57,000 psi range, the European CIP Pmax for the 7x57, and the velocities were commensurate with the listed data.

322193

Now, ponder what the actual velocity would be if we ran the psi up to 60,000 for use in a modern action and put a 24.5" barrel on it giving the same effective barrel length as the AR 7mm had. We'd be pushing that 120 gr bullet up into the 3200 - 3300 fps range. The 7x57 case has the capacity to do the with the 120 gr bullet, the 7mm Valkyrie does not. Then let's consider what happens if a heavier bullet is used in either. The case capacity of the Valkyrie is eaten up very quickly, not so much in the 7x57.

Case capacity matters. With all else comparatively the same the 22 H will never equal the 221 Rem, the 7.62x39 the 30-30, the 300 Savage the 308W, the 308W the 30-06, the 30-06 the 300 H&H or the 300 H&H the 300 Win Mag. There are hundreds of other examles for each caliber. Fact is, the 7mm Valkyrie will never "equal" or "be the same as" the 7x57 unless, perhaps, there is some 120 gr 7x57 ammo loaded out there to SAAMI specs or less(?). When hand loaded or with heavier bullets the Valkyrie just won't cut it in comparison.

It's interesting though and guys can play with it all they want and see nothing wrong with it as I also play with a lot of cartridges just for fun. However, there is no need to unjustly compare a new cartridge a fine old cartridge to justify it. The 7mm Valkyrie fits in an AR15 and the 7x57 does not. If one wants a 7mm AR15 it appears the Valkyrie is a good choice.

[Harter66]

I used a 6.8 SPC and got a 27-130 to almost 2500 fps MV ........ The primer vaporized , but , I almost got 2500 fps with the 141 gr paper patch.....

The 2.26 OAL limit in the magazine means you have to go wider to get capacity. With a 284 case pushed back to 1.8 or so it'd be close but the bolt dogs and barrel extension get pretty thin. At 2.10 the 284 case is all but a dead heat with the standard 280 Rem so shortened 3/10s would be right there with the Mauser .

[Loudenboomer]

I built up a 7mm-08 Ar-10 on a DPMS receiver, 1-8 twist 22" X-Caliber barrel with rifle +2" gas system and Superlative Arms adjustable gas block. StaBall 6.5 powder is a bit on the slow side but has been working well. I set the rifle up to shoot the JLK VLD 180 match bullet. I have many thousands of these bullets and was the idea behind the project albeit little on the heavy side for 7mm-08. Not an Ar-15 but it provides many of the big bullet attributes of the 7mm Mauser.

[35 Rem]

I can't take an AR or any semi auto seriously for anything but self-defense. Reason being that I don't want to either lose all my brass or spend tons of time poking around in the grass looking for it. I'm all for the existence of AR's or other rifles based on military guns for self defense but my take on that is to buy 2 or 3 of them, set aside say 10,000 rounds of ammo for it and then go to a true sporting rifle for most shooting or hunting. Losing brass is too big a negative for a reloader in my opinion.

One thing I think that drives the enthusiasm for AR's among younger shooters is that they have been raised with computers in their hands since day one. In the computer world 3 years old means obsolete and they tend to bring that same thinking along when they get into guns. If it's old, it HAS to be obsolete, and I can EASILY come up with something that will outperform it they think. Tain't so but the still think it.

[trebor44]

WOW! Marketing hype will suck in anyone who left their brain in 8th grade! Note: this is the reading level for the WSJ daily paper.

[Wolfdog91]

I can't take an AR or any semi auto seriously for anything but self-defense. Reason being that I don't want to either lose all my brass or spend tons of time poking around in the grass looking for it. I'm all for the existence of AR's or other rifles based on military guns for self defense but my take on that is to buy 2 or 3 of them, set aside say 10,000 rounds of ammo for it and then go to a true sporting rifle for most shooting or hunting. Losing brass is too big a negative for a reloader in my opinion.

One thing I think that drives the enthusiasm for AR's among younger shooters is that they have been raised with computers in their hands since day one. In the computer world 3 years old means obsolete and they tend to bring that same thinking along when they get into guns. If it's old, it HAS to be obsolete, and I can EASILY come up with something that will outperform it they think. Tain't so but the still think it.

As a 26 yr reloader and shooter ....all I can say is.....ARE YOU SERIOUS LOL . Sweet Lord have mercy

[M-Tecs]

I can't take an AR or any semi auto seriously for anything but self-defense. Reason being that I don't want to either lose all my brass or spend tons of time poking around in the grass looking for it. I'm all for the existence of AR's or other rifles based on military guns for self defense but my take on that is to buy 2 or 3 of them, set aside say 10,000 rounds of ammo for it and then go to a true sporting rifle for most shooting or hunting. Losing brass is too big a negative for a reloader in my opinion.

One thing I think that drives the enthusiasm for AR's among younger shooters is that they have been raised with computers in their hands since day one. In the computer world 3 years old means obsolete and they tend to bring that same thinking along when they get into guns. If it's old, it HAS to be obsolete, and I can EASILY come up with something that will outperform it they think. Tain't so but the still think it.

These work very well as a brass catcher.
https://brassgoat.com/

These are the best but pricy. I love mine. When shooting prairie dogs, I load 7 20 round mags and shoot till it's time to load mags and empty the 140 rounds of brass in the catcher. The time spent loading also allows for the barrel to cool some. I have one spot that normally is an 800 round plus day with 75% kill percentage.
https://www.tacticalbrassrecovery.com/operator-ar15-ar10-scar/

Mine is an older version. I got it when they first came out. Mine has caught maybe 100K piece of brass. I normally shoot between 5K and 6K a year out of the AR. Only time brass hits the ground is when I foget to close the zipper on the bottom.

[WILCO]

I have a soft spot for the 7mm Mauser.

[dverna]

I can't take an AR or any semi auto seriously for anything but self-defense. Reason being that I don't want to either lose all my brass or spend tons of time poking around in the grass looking for it. I'm all for the existence of AR's or other rifles based on military guns for self defense but my take on that is to buy 2 or 3 of them, set aside say 10,000 rounds of ammo for it and then go to a true sporting rifle for most shooting or hunting. Losing brass is too big a negative for a reloader in my opinion.


That is where I am as well.

I have five AR's for if/when the SHTF but have little desire to shoot them much. Even though .223 brass is cheap, why go hunting for it and pick it up after doing all the prep work? Prefer bolt actions and lever actions when shooting off the bench.

Wolf makes a good point about being able to have a bunch of different calibers by swapping uppers for those who like lots of "toys". When I got my first AR, I was going to travel that road. I used to be like that when I was younger but am a minimalist now.

My CF rifle needs are simple. The .223 and .308 cover self-defense close or far (as far as I can shoot anyway) and varmints/game. I have a few .30/30's but they are there in case the idiots ban AR's and I need an effective "combat rifle."

If I miss a 300 yard shot at a varmint due to wind drift, that I would have hit with a 6mm ARC, it is not the end of the world. Plus, I prefer carrying my little Howa mini-Mauser instead of lugging around an 8+ lb AR that makes me look like a mall ninja.

ARs have their place. I am "old school" when it comes to shooting and hunting.

[Wolfdog91]

On the subject of hunting brass... Legit $10
https://uploads.tapatalk-cdn.com/20240121/7a3beb65986821eb604b20ed6ea5ac1b.jpghttps://uploads.tapatalk-cdn.com/20240121/a9c57e4a5f45a8c944044adb91019e46.jpg

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[Rapier]

Wolfdog, good to see you are looking into increasing the performance of your AR platform. Bruce has some great cartridge designs, over 30, to his credit. Many of his designs have been copied and changed a bit, with a rename by the big cartridge makers. The 7mm Val brass is now offered by Star-Line. The 24 Varmit is the 7mm Val necked down and blown out, both based on the 6.8 SPC case. I just finished up a 24 Varmit build with an 18" 1-8 twist SS barrel, interesting concept, and Varmint Magazine did a two year series of tests on the cartridge in the AR platform with a good write up. Was originally the 24 GPC, changed the name to the 24 Varmint as a tribute to Varmint Magazine for taking the time and effort to do a fair test of the cartridge and the chambering in the AR-15 platform. Pictures of my 24 brass in forming stages before the name change. The 24ff is fire formed. Makes for a very versatile 6mm semi auto rifle.

[Slugster]

Use AR-10 platform and be happy. Build a true 7mm Mauser on that platform and I would be first or second in line to purchase one. I have always loved the 7mm Mauser as it was the cal of the first surplus rifle that I bought. During deer season I reach past more modern rifles to get out my 7mm Mauser Frankenrifle that I built from parts laying around the shop. Can put as many through a ragged hole at 100 yards as you want. Makes DRT hits on deer.

[Wolfdog91]

Use AR-10 platform and be happy. Build a true 7mm Mauser on that platform and I would be first or second in line to purchase one. I have always loved the 7mm Mauser as it was the cal of the first surplus rifle that I bought. During deer season I reach past more modern rifles to get out my 7mm Mauser Frankenrifle that I built from parts laying around the shop. Can put as many through a ragged hole at 100 yards as you want. Makes DRT hits on deer.

AR10 are just extra weight extra parts three different patterns to deal with , extra pain. Not to mention Ive only been able to find two sources for 7mm Mauser brass one of witch is once fired range brass. Though 6.5x57 brass is kinda expensive it's good quality brass and not super hard to find. Not to mention you can form it from 6.5 creed which is everywhere. I Mena you could talk to magowen since they do .7mm barrels and for a extra $60 they will do a custom chambering .

[Wolfdog91]

Wolfdog, good to see you are looking into increasing the performance of your AR platform. Bruce has some great cartridge designs, over 30, to his credit. Many of his designs have been copied and changed a bit, with a rename by the big cartridge makers. The 7mm Val brass is now offered by Star-Line. The 24 Varmit is the 7mm Val necked down and blown out, both based on the 6.8 SPC case. I just finished up a 24 Varmit build with an 18" 1-8 twist SS barrel, interesting concept, and Varmint Magazine did a two year series of tests on the cartridge in the AR platform with a good write up. Was originally the 24 GPC, changed the name to the 24 Varmint as a tribute to Varmint Magazine for taking the time and effort to do a fair test of the cartridge and the chambering in the AR-15 platform. Pictures of my 24 brass in forming stages before the name change. The 24ff is fire formed. Makes for a very versatile 6mm semi auto rifle.

Honestly I just find this stuff really cool. I love ofl calibers but I realize if it want for people like Bruce thinking similar back in the day alot of stuff wouldn't be around to day if they just went with " well this already works why change it ?!" I honestly hate the term " if it ain't broke don't fix it " with an amazing passion.
I can only imagine what people where saying back in the day when we went from 30-40 krag to 30-06 or they necked a 30-06 down to .25-06. It's not the fact something nif broken if it's old it's stuff advances what was cutting edge tech in cartridge design 50years ago just my not be necessary now days.
I Mena I thought people would find it cool that the newer generations would be revisiting the old cartridges and trying to improve them or do something similar in a modern deal. What's so bad about some kid saying "man id love to play with something similar to a 7mm Mauser or .257 Roberts but I can't find one or can't afford a cutome rifle brass ect, let me get this wild cat based in it that I can use in my AR".Better then just letting it die completely there was actually a big resurgence with 6.5 sweede in my generation after the creedmore cam out . Why ? We liked the creedmore and heard about the sweede being its grand dad so we started playing with those. But I'm ranting now.

Anyhow yeah Bruce has some cool stuff and I'm really wanting to try one of his one day. 24 goc does look cool.

[M-Tecs]

I can only imagine what people where saying back in the day when we went from 30-40 krag to 30-06 or they necked a 30-06 down to .25-06. It's not the fact something nif broken if it's old it's stuff advances what was cutting edge tech in cartridge design 50years ago just my not be necessary now days.
.

You think that bad just read the comment about the Army's new cartridge the 6.8x51 and the XM7 & XM250. Like you they are trying to maximize perform in a specific magazine size.

[MaryB]

I can't take an AR or any semi auto seriously for anything but self-defense. Reason being that I don't want to either lose all my brass or spend tons of time poking around in the grass looking for it. I'm all for the existence of AR's or other rifles based on military guns for self defense but my take on that is to buy 2 or 3 of them, set aside say 10,000 rounds of ammo for it and then go to a true sporting rifle for most shooting or hunting. Losing brass is too big a negative for a reloader in my opinion.

One thing I think that drives the enthusiasm for AR's among younger shooters is that they have been raised with computers in their hands since day one. In the computer world 3 years old means obsolete and they tend to bring that same thinking along when they get into guns. If it's old, it HAS to be obsolete, and I can EASILY come up with something that will outperform it they think. Tain't so but the still think it.

They make brass catchers for the range... hunting I don't worry about losing 2 or 3 pieces of brass... https://www.amazon.com/Caldwell-Brass-Catcher-Picatinny-Resistant/dp/B00EB5OU0Q?th=1

My 6.5 Grendel performs as well as a .308... so yes new cartridges can perform as well as old designs in the AR-15! I use it on deer and feral hogs...

[lar45]

I like guns of all shapes and sizes. I've got most everything covered from 22lr to 470NE in rifles and up to a 70cal double barreled pistol in Handguns. Does this mean I'm done and don't want anymore? Nope!
I just built a 358cal AR15 that beats stock performance of the 35 Remington, 200s at almost 2400 and 180s at 2571. It won't be the best all around hog and deer rifle, but I'm betting it will do alright within 250yds.

[charlie b]

I have been tempted by the AR platform. My 'defense' gun is a Garand :) I don't shoot it much anymore. 'Wastes' too much ammo. :)

If you want 'plug and play' with a bolt rifle and excellent accuracy you can have it. Savage is designed for it. Swap a barrel in about 20min. New bolt head for any size case you want. If you get a long action there isn't much of a limit on what cartridges you can use, unlike the AR limitations. There are Remage barrels for those with 700 pattern actions. Ruger RPR. And you can get a chassis for any of them if you really want the look, or a plastic, laminate or wood stock. Then you have a rifle with the potential of excellent precision, even bench rest or Fclass competitive levels. No gunsmithing required.

[MtGun44]

Larry is right. I love my 7x57 and this isn't it. I like and use ARs, too, but the action length just won't let
you have the powder capacity needed.

Use an AR-10 platform, and you can sort of do it, but the 7x57 is longer than .308. So, use 7-08....which can
pretty much match 7x57 (and with wimpy loading limits on 7x57 for antique guns) or beat it.

Load 7x57 to modern pressures in modern rifles, great cartridge. I hunted with it in Africa, using 160 Nosler Partition
bullets at 2750 fps. Didn't shoot anything twice, including kudu. Great cartridge, this thing is interesting
but something like 7 BR, not 7x57, or not even 7-08.

Bill