358 YETI

[CWLONGSHOT]

I’m a 35 cal nut!!

couple years back I looked hard at this one but decided upon the 357 AR a friend in another forum was building. Brass cases was a PIA to make as there was no 223 basic then.
Figured why re create the wheel. I mean as cool as another 35 is Id just do a ar10 and a 358. A caliber that started my 35 cal obsession. I know I know bigger longer heavier... I didn’t do that. I also never completed a 357AR. But jumped upon the 350 when released only to be let down with the foolish 9mm long it really is. But I have grown to like it.
I’m waitin in a few sales and I’m gonna order a CVA Scout in 35 Remington. Two buddies have them and don’t shut up about the lo cost and accuracy. (I was a handihaulic no so long ago and appreciate a cheap SS chooter.
Project looks like your enjoying it! I’ll enjoy reading more posts. Have fun hope it’s a shooter for ya!

CW

 

[wquiles]

If you look at the 358YETI platform, it is not meant for subsonic, but rather supersonic usage. The majority of loads are built around the 180gr and 200gr jacketed bullets, achieving from a 16" barrel more power than a 35 Remington, and close to the lower-end of the 358 Winchester loads, with 180gr at 2550fps and 200gr at 2450fps:
358YETI reloading data

There is also a Google file with the results from actual users that I am attaching here.

Once ranges open again, I am of course not going to shoot for that level to start with, but I figure a GC PC 200gr cast at close to 2000fps would be a good starting point, so I started making dummy rounds with the same bullet I shot in the 358Win, the 200gr Lee:



For the mags, I am using Lancer mags, with the Tromix 450 bushmaster follower. To make the mags work with the 358YETI, one "bends" the back of the lips inward until they consistently hold the rounds under spring pressure:



AND to help the rounds "point upwards", to load reliably, I also slightly modified the front by making it slightly narrower so that it goes up higher than normal, so that on the last round it is pointing properly and not "flat":



This is how the inserted magazine looks like on the last round:



This is how the 6x dummy rounds I made work with the modified magazines - easier to see above, but hard to tell in this picture below, but the metal lips do grab the back of the case much higher:



I modded and tested 2x mags that seem to work on the bench:



Short video of loading rounds under full spring pressure

 

[popper]

Garland is open but don't know how long. Abbott set the precedence but it may change at any time. Call before you go.

 

[Ian]

Looks like it feeds flawlessly, now all you need is a range test. Wish you weren't so far away becase I'd just give you the gate code and directions to my shooting bench and tell you to have at it.

The expected ballistic capabilities are extremely impressive, I see now what got you going on this project. This will be a quite a pig hammer should you take interest in hunting them.

 

[Hawk]

Garland is open but don't know how long.

Was the range crowded the last time you were there?
I need to work up some high end 9mm Mihec 124gr. HP loads.

 

[wquiles]

Got a QuickLOAD question. Being a "recent" wildcat my copy of QuickLOAD does not have the 358Yeti. From the "official" specs here:
358 Yeti

Case length: 1.646"
Case water capacity: 44-46gr water
For my 200gr bullet, COL is about 2.160"
Max chamber PSI - approx 58-59k (from this data)

I know QuickLOAD is just an approximation to actual values, but what else can I adjust in QuickLOAD to get the 358Win settings to more closely approximate the 358 Yeti wildcat?

 

[Brad]

I would weigh the water capacity of your cases. The most accurate that is the better the results.
I did that for my 30 XCB and the results were often within 25 fps of my chrony

 

[wquiles]

Thanks Brad. I measured one of my fully prep cases and it came at 44.9gr of water. I loaded some rounds with CFE BLK, and I will verify with the LabRadar once I get to the range to try them out

 

[Brad]

You adjust start pressure a bit to get the measured and predicted velocities to agree more closely after a first run. Then try a few other loads to see how well they track.

Outside of a few straight cases I have always found QL to be quite close.

 

[Rockydoc]

Non-reciprocating? Does that mean it is not semi-automatic, but a straight pull bolt action?
I know next to nothing about AR type guns. I don't care much for semi-auto guns, they scatter brass. With brass as difficult to acquire as this 358 Yeti I can see why you chose a non scatter option(if that is what this is).

 

[wquiles]

It is an AR-15, so it is inherently semi-automatic. That being said, since mine has an adjustable gas block, so it you close it completely, the closed gas block turns the rifle into fully manual rifle, and you would have to pull back to eject the fired case, and let go to pickup a new round from the magazine, time and time again for every single round.

The non-reciprocating side charging mechanism in my rifle means that the charging handle on the left side of the receiver "stays put" as the rifle goes through the semi-auto cycling after every shot. That external lever is NOT moving at all. You only have to pull and release once, to drop the bolt on a round. So there are no "moving parts" outside of the receiver while in operation (much like a basic AR-15 with the standard rear charging handle, which stays put while the AR-15 is firing rounds).

This is unlike the more common method for side charging where one bolts "an extension" to the actual bolt of the rifle (typically on the right side of the receiver which has to be modded with a slit/cut for clearance) which "does" move back and forth with every round fired since it is literally part of the bolt. This is thus a reciprocating side loading mechanism.

Makes sense?

 

[Rockydoc]

Yes, your explanation makes sense.
It is having a gun that scatters brass all over the place in normal operation that doesn't make sense to me . If I were using an AR for what it was intended to be used for I wouldn't care a bit what happened to the brass once the trigger was pulled, and the bigger the magazine capacity the better. Thankfully I haven't ever had to do that.

 

[chad_a_hill]

If you look at the 358YETI platform, it is not meant for subsonic, but rather supersonic usage. The majority of loads are built around the 180gr and 200gr jacketed bullets, achieving from a 16" barrel more power than a 35 Remington, and close to the lower-end of the 358 Winchester loads, with 180gr at 2550fps and 200gr at 2450fps:
358YETI reloading data

There is also a Google file with the results from actual users that I am attaching here.

Once ranges open again, I am of course not going to shoot for that level to start with, but I figure a GC PC 200gr cast at close to 2000fps would be a good starting point, so I started making dummy rounds with the same bullet I shot in the 358Win, the 200gr Lee:
View attachment 14177


For the mags, I am using Lancer mags, with the Tromix 450 bushmaster follower. To make the mags work with the 358YETI, one "bends" the back of the lips inward until they consistently hold the rounds under spring pressure:
View attachment 14178


AND to help the rounds "point upwards", to load reliably, I also slightly modified the front by making it slightly narrower so that it goes up higher than normal, so that on the last round it is pointing properly and not "flat":
View attachment 14179


This is how the inserted magazine looks like on the last round:
View attachment 14180


This is how the 6x dummy rounds I made work with the modified magazines - easier to see above, but hard to tell in this picture below, but the metal lips do grab the back of the case much higher:
View attachment 14181


I modded and tested 2x mags that seem to work on the bench:
View attachment 14182


Short video of loading rounds under full spring pressure

What round count can you load the mags to?

That’s the one question I have never heard any info about.

 

[wquiles]

Apologies for the late reply, as I had the camping trip with my son this weekend.

On my converted 30-rnd magazine, I can barely fit 10x of the 358 YETI rounds.

 

[Ian]

Wow, I would have thought 12-13 at least. I can comfortably run 10 .458 Socom cartridges in an unmodified 30-round magazine...and they truly single-stack.

 

[wquiles]

Maybe there is a way to push a couple more, but it was enough work for me to get the 10x in there

I should note that with the pandemic, and the shooting range running at 1/2 capacity (distancing), I have "yet" to fire this rifle - hopefully soon.

 

[wquiles]

OK, so yesterday I "finally" got to try this rifle. Wow, talk about a pandemic related side-effect

Shooting my 200gr Lee GC PC-lubed bullets, using CFE Blk powder. Per the research I found based on j-bullets I estimated the max. charge to be about 36.4gr, and 90% is a good place to start, which gave me about 33.0gr to start. I then loaded some at 33.5gr and 34.0gr.

- I started with the gas port totally closed at 33.0gr. All good. No stuck cases, bullets hitting paper target - you know - normal. I was brave enough that I had my form-1 Titanium suppressor installed as well.

- I opened the gas port about 1/2 way, and tried the 33.5gr. All good, but to my surprise, I also got full cycling and bolt open on last round

- I then tried the 34.0gr. No problems with the first 4x, but the 5x case would not eject - got stuck. I wasn't supper stuck, so I was able to extract it right there at the range, so it looks like I found my limit. I will stick with 33.5gr to continue to fine-tune the load.

Per my lab radar, ave for the 33.5gr was 2146fps, or just about 2050 ft.lb at the muzzle (temp was about 60F). Not bad at all for my first every rounds on my first ever wildcat on a brand new ar

 

[fiver]

that's running 50 maybe 75 fps behind the 7.62X39 with a 125.
I'd have no complaints right there at 33.5.

 

[Ian]

That's just about. 35 Remington/20" barrel territory there. Not too shabby. My only concern is if pressure is enough to stick a case in a dirty, suppressed chamber, how much bolt thrust is it generating? As I recall the .473" bolt face should be limited to about 36,000 PSI in an AR-15. .308 brass shouldn't start sticking from excessive pressure until about 70K. Did the extractor tear a chip out of the rim?

 

[Ian]

I don't have an updated version of QL but ran the numbers with several other powders and keeping at 36K max it's just under 2,000 fps. H335 and Reloder 7 are the best bets. I tried following the link to the data but got a 404.