A 358 YETI that is. ;D
After reading sqlbullet's post a few years ago about his AR-10 build in 358 Winchester I was very intrigued...and a bit jealous. I've always liked the 358 Win, I've thought it combined a good balance of power, speed and size but AR-10's aren't mil-spec and what company to go with was always a question.
In doing research last year, I stumbled across Mad Dog Weapon Systems and the 358 YETI that offers close to 358 Win performance in the AR-15 platform. I've built several AR-15's over the years in various calibers and had plenty of spare parts laying around so, while I was waiting for a new batch of barrels to be made, I started planning the build.
I had most of the parts when the barrels came in and everything arrived while I was recovering from surgery last month. (appendix) This worked out perfectly as it kept me from being bored out of my mind being off work. My daughter was in town visiting the weekend I took it out to fire form the first batch of brass and snapped this pic.
(https://redirect.viglink.com/?format=go&jsonp=vglnk_157337205807513&key=ccc2217bc2b75c4bdf5f7e57267f0464&libId=k2sp1udh010009xy000DAf2487lq7&loc=https%3A%2F%2Fmdws.forumchitchat.com%2Fpost%2Fmy-first-big-bore-ar-10310658%3Fpid%3D1309904143&v=1&out=https%3A%2F%2Fd28lcup14p4e72.cloudfront.net%2F171658%2F4851791%2Fvlcsnap-2.png&ref=https%3A%2F%2Fmdws.forumchitchat.com%2F%3Fforum%3D467590&title=My%20first%20Big%20bore%20AR%20-%20Modern%20Sporting%20Rifle%20Evolution&txt=%3Cimg%20alt%3D%22vlcsnap-2.png%22%20class%3D%22bbc_img%22%20src%3D%22https%3A%2F%2Fd28lcup14p4e72.cloudfront.net%2F171658%2F4851791%2Fvlcsnap-2.png%22%3E)
I'm still in the very early stages of load development but the accuracy seems promising.
This group is with Speer 180 gr. Hot cores at 2540 f.p.s.
(https://redirect.viglink.com/?format=go&jsonp=vglnk_157337446862014&key=ccc2217bc2b75c4bdf5f7e57267f0464&libId=k2sp1udh010009xy000DAf2487lq7&loc=https%3A%2F%2Fmdws.forumchitchat.com%2Fpost%2Fmy-first-big-bore-ar-10310658%3Fpid%3D1309904143&v=1&out=https%3A%2F%2Fd28lcup14p4e72.cloudfront.net%2F171658%2F4850555%2F74369455_10214715966800768_8859990912822935552_n.jpg&ref=https%3A%2F%2Fmdws.forumchitchat.com%2F%3Fforum%3D467590&title=My%20first%20Big%20bore%20AR%20-%20Modern%20Sporting%20Rifle%20Evolution&txt=)
Hornady 200 gr. FTX at 2400 f.p.s.
(https://redirect.viglink.com/?format=go&jsonp=vglnk_157337455867815&key=ccc2217bc2b75c4bdf5f7e57267f0464&libId=k2sp1udh010009xy000DAf2487lq7&loc=https%3A%2F%2Fmdws.forumchitchat.com%2Fpost%2Fmy-first-big-bore-ar-10310658%3Fpid%3D1309904143&v=1&out=https%3A%2F%2Fd28lcup14p4e72.cloudfront.net%2F171658%2F4850559%2F75653325_10214715977721041_2959708400860004352_n.jpg&ref=https%3A%2F%2Fmdws.forumchitchat.com%2F%3Fforum%3D467590&title=My%20first%20Big%20bore%20AR%20-%20Modern%20Sporting%20Rifle%20Evolution&txt=)
Jeff
Looks promising for sure!!
I looked at this caliber too. Im a 35 cal nut!
Its logged away maybe one day!
CW
I too am a .358 Winchester fan! I currently have 2- a custom Mauser and a Ruger #1. Like you, I've often thought about a .358 AR-10, but those plans are still stuck in the "pending" file. Now you throw a monkey wrench into those plans by telling us about the .358 Yeti?
For those of us who don't know, would you share the story of this cartridge? I can't speak for anyone else but I have an AR-15 that could be a perfect platform for a remodel and am very curious about it.
Another 35 caliber nut here. What is the twist of the barrel from Mad Dog? I looked at their website and they claim that the cartridge shoots everything including 9mm and .357 light and heavy pistol bullets to a 250gr bullet. Sounds more like somebody has life and bullchips confused. That's quite a spread for the same twist. While I didn't do the loading, my brother had one of these uppers for a short time. He couldn't get any where near the velocity they claim. With AA1680 and AA2200 powders, he couldn't get a 180 gr Speer bullet over 2200'ps and that left him with bent head rims on the military brass and flat primers. The brass was not usable for another run thru the gun. He had some Winchester 250 Silver Tips that he tried. Max load was just over 1900'ps. Considering the 35 Whelen is a much larger case and his Whelen is sporting a 22" barrel yet it has to be pushed pretty hard to hit the same velocity as the considerably shorter and smaller case capacity 358 Yeti. I find the claims to be highly suspect. While I would love to have a 35 caliber on an AR 15 rifle, I would much rather hear that the gun shoots right at the same velocities as a 30-30. I would rather have the weight and larger wound channel of the 35 caliber bullet. But the claims seem so far fetched for this round that I think I'll stick with my old Marlin 336SC with Ballard rifling. It shoots tiny cloverleafs at 100 yds amazingly and will even shoot the 250gr bullet with a case full of IMR4064. The old Marlin hits hard. That's why I'd love to have something like this Yeti in an AR platform but the claims are nutz.
Quote from: Trapper6L on November 10 2019 07:10:55 PM MST
Another 35 caliber nut here. What is the twist of the barrel from Mad Dog? I looked at their website and they claim that the cartridge shoots everything including 9mm and .357 light and heavy pistol bullets to a 250gr bullet. Sounds more like somebody has life and bullchips confused. That's quite a spread for the same twist. While I didn't do the loading, my brother had one of these uppers for a short time. He couldn't get any where near the velocity they claim. With AA1680 and AA2200 powders, he couldn't get a 180 gr Speer bullet over 2200'ps and that left him with bent head rims on the military brass and flat primers. The brass was not usable for another run thru the gun. He had some Winchester 250 Silver Tips that he tried. Max load was just over 1900'ps. Considering the 35 Whelen is a much larger case and his Whelen is sporting a 22" barrel yet it has to be pushed pretty hard to hit the same velocity as the considerably shorter and smaller case capacity 358 Yeti. I find the claims to be highly suspect. While I would love to have a 35 caliber on an AR 15 rifle, I would much rather hear that the gun shoots right at the same velocities as a 30-30. I would rather have the weight and larger wound channel of the 35 caliber bullet. But the claims seem so far fetched for this round that I think I'll stick with my old Marlin 336SC with Ballard rifling. It shoots tiny cloverleafs at 100 yds amazingly and will even shoot the 250gr bullet with a case full of IMR4064. The old Marlin hits hard. That's why I'd love to have something like this Yeti in an AR platform but the claims are nutz.
If this is the reality of this Yeti cartridge, I'm building a .358 Win upper for my AR-10.
Quote from: woods_walker on November 10 2019 08:11:56 PM MST
If this is the reality of this Yeti cartridge, I'm building a .358 Win upper for my AR-10.
Let me know if you wanna talk this through. I build a 358 Win AR-10 a few years back using a KAK 16" barrel. I have been very happy but I did learn a few lessons.
I went with a lightweight titanium BCG and it would not cycle heavy 358 bullets all the way into the chamber. They would hang up with the extractor trying to get over the rim. I sacrificed the weight and went back to a standard steel BCG and all was fine.
My chamber was also short for long nose bore riding type cast bullets. I bought throat reamer and extended the free-bore a bit. While this probably had a bad effect on accuracy, I never meant this to be a tack driving gun at 800 yards. It is still easily minute of coke can at any reasonable range.
I still find the barrel profile a bit meaty for my needs, and if I ever execute on buying an engine lathe, I will probably turn the profile down a bit.
Overall, a very fun little carbine.
Quote from: woods_walker on November 10 2019 09:31:48 AM MST
For those of us who don't know, would you share the story of this cartridge? I can't speak for anyone else but I have an AR-15 that could be a perfect platform for a remodel and am very curious about it.
The barrels available are 16" & 18" with a 1-14" twist. MD uses a proprietary hardened bolt and barrel extension to withstand the chamber pressures.
Trapper6L. I'm not sure what claims you were reading, this caliber only started shipping in 2017, MD states usable bullet weights up to the Speer 220 gr with the preferd bullet being the Speer 180 gr. Hot Core. Recommended powders are Accurate 1680 and Shooters World Black out, although I've read Hodgdons CFE Blk is showing promise with the 200 gr. Hornady FTX and the Speer 220 gr.
The chamber reamer was made with using cut down Lake City military brass in mind, although you can use any 308, 30-06, 8 Mauser based caliber brass as the parent case. The issue becomes neck wall thickness and case capacity. The chamber neck is cut pretty generous so that you don't have to turn the necks to get them to chamber. (fired case necks measure .399)
So far, I've tried 30-06 brass from PPU, R-P & Federal, 308 brass from WCC and Lake City fired 308 blanks. The WCC and the LC blanks offer the best compromise between case neck thickness and powder capacity.
Making the cases is fairly straight forward and easy. Here's a vid on it.
https://www.youtube.com/watch?v=ayy3ApJgYd0 (https://www.youtube.com/watch?v=ayy3ApJgYd0)
Although I prefer to anneal before forming.
My barrel is 18" and I've had no problem getting the Speer 180 gr. over 2500 f.p.s.
With the SWBO powder, 2600 f.p.s. is doable, but accuracy is crap. My gun likes 2540 f.p.s. with either 1680 or SWBO with a slight accuracy advantage to SWBO.
I can get the Hornady 200 gr. FTX up to 2400 f.p.s. but it will only shoot about 2" groups. Back it down to 2330 f.p.s. and it shoots 1" groups.
It's been a fun project so far. Future testing will include the Speer 220 gr. bullet, 140 & 158 gr. 357 bullets and stretching it out to 200 & 300 yards. I'll keep you posted.
Jeff