358 gremlin, 358 bfg....???anyone..anyone

[worksalot]

A friend and I have been looking at these calibers/caliber for awhile now(358bfg/358 gremlin)...awaiting some word on them in an AR platform. My friend has been in contact with a couple of folks about them but keeps getting the call me in a couple months run around...the last post on a build was early 2011 from what I found here. Does anybody know... does it work in an AR or not? Just looking for some good facts. I think it would be a great gun to play with and I all ready have the grendel.

 

[fireball168]

My friend has been in contact with a couple of folks about them but keeps getting the call me in a couple months run around...

Well, since the only "folks" that build either of those cartridges is me....

The Gremlin will most certainly work in an AR. Our dedicated magazine project didn't make it through production before C-Products went out of business. Currently, the best magazine I've found is the PRI 6.8 SPC, and certain variations of that are better than others. Had high hopes for the Lancer modified for the 7.62x40, but the polymer flexes too much with the fatter cartridge. I don't market this cartridge very hard for the AR-15 as I'm not satisfied with the current magazine offerings and the feeding reliability using them. Will make another run for dedicated magazines this year at SHOT.

Olympic Arms is the only current source for WSSM uppers to convert. After you get one bought and rebarrel it, it is an expensive proposition. I've got high hopes that Remington will release service components for their 30 RAR upper receivers and provided they are of higher quality that the Olympic bits, will use them in the future for 358 BFG AR-15 uppers.

There are others out there that market a 358 WSSM variation on the Olympic WSSM receivers. Other than selling brass and dies to some of their customers, I've had no experience with them.

Bryan

 

[42769vette]

Well, since the only "folks" that build either of those cartridges is me....

The Gremlin will most certainly work in an AR. Our dedicated magazine project didn't make it through production before C-Products went out of business. Currently, the best magazine I've found is the PRI 6.8 SPC, and certain variations of that are better than others. Had high hopes for the Lancer modified for the 7.62x40, but the polymer flexes too much with the fatter cartridge. I don't market this cartridge very hard for the AR-15 as I'm not satisfied with the current magazine offerings and the feeding reliability using them. Will make another run for dedicated magazines this year at SHOT.

Olympic Arms is the only current source for WSSM uppers to convert. After you get one bought and rebarrel it, it is an expensive proposition. I've got high hopes that Remington will release service components for their 30 RAR upper receivers and provided they are of higher quality that the Olympic bits, will use them in the future for 358 BFG AR-15 uppers.

There are others out there that market a 358 WSSM variation on the Olympic WSSM receivers. Other than selling brass and dies to some of their customers, I've had no experience with them.

Bryan

from the horses mouth

 

[worksalot]

thanks for the info

My buddy had mentioned the magazine issue. I am interested in the 35 gremlin and I guess I figured the 6.5 grendel mags would work with maybe with some feed lip tweaking? But you have probably tried that. I was not trying to start any stink..sorry if it seemed that way. We are just really interested in the concept. I would still be interested in an upper even if it has mag issues..maybe I could help?

 

[Skip]

I am working with a "standard" MGM 358 WSSM on the Encore platform right now. The loads that I am working on are developing well over 2500fps with a Nosler 225gr Accubond bullet. The accuracy is okay, 1MOA if I do my part.

I got mine from Just Hunt in Wabash and they are great folks to deal with. From what I hear, the BFG has some slight changes that make it proprietary while the MGM barrel uses a standard reamer.

If I get the kinks worked out of this thing, it will be THE deer gun for Indiana! That is, until the case length grows to 1.8"

 

[42769vette]

I am working with a "standard" MGM 358 WSSM on the Encore platform right now. The loads that I am working on are developing well over 2500fps with a Nosler 225gr Accubond bullet. The accuracy is okay, 1MOA if I do my part.

I got mine from Just Hunt in Wabash and they are great folks to deal with. From what I hear, the BFG has some slight changes that make it proprietary while the MGM barrel uses a standard reamer.

If I get the kinks worked out of this thing, it will be THE deer gun for Indiana! That is, until the case length grows to 1.8"

i have a mgm 358 bfg barrel. they will make whatever you want, contact fireball if interested

 

[Skip]

The reamers between the two are enough different that MGM will not sell the BFG to anyone but the owner of BFG. I'm fine with that. If they developed something new and great, more power too them. I'll just work with their standard 358WSSM and see what I can get out of it.

A 225gr Accubond @ 2500fps is going to be a force to recon with. Mostly on the other end.

 

[fireball168]

From what I hear, the BFG has some slight changes that make it proprietary while the MGM barrel uses a standard reamer.

Hear this:

There are no less than 17 different variations of the 358/25 WSSM. There is no "standard" reamer for 358 WSSM. If you call and ask PTG or JGS for a 358 WSSM reamer, they'll ask you which one you'd like.

Between them all are different base dimensions, shoulder angles, case length, neck lengths, shoulder to neck junction location, neck diameters, throat length, you name it.

Between the suppliers of 358/25 WSSM dies, there is better than .006" difference in neck tension alone, as each one was cut to somebody's chamber print that was called "standard" at that time.

The 358 BFG chamber is the 358 BFG. The 358 BFG dies are 358 BFG dies.

BFG customers receive starting load data and loads that have been fed back to me through my customers.


I've always been more than happy to assist customers that bought generic products in determining what their chambers are, what their neck diameter and brass neck thickness needs to be, what their throat length is, and then matching up a set of generic 358/25 WSSM dies to work the best with their combination.

One thing I will not assist with is providing any sort of loading data for generic products.

 

[Skip]

fireball, if you took my statement as an afront to you or your caliber, it surely wasn't intended as such.

My rifle is what it is, and what I was told from MGM themselves, from THEIR standard reamer. Whatever that is.

My cases were built by Just Hunt, and they will work well until I start making my own.

The whole idea of the caliber is what intrigues me. I am a handloader that likes to experiment rather than a hunter that is looking to get the most powerful gun to take to the field.

MGM has a superb reputation and since this is my first venture into the Encore platform, along with a 44Mag Thompson Center factory carbine barrel and their 209X50 muzzle loader, I thought that going this route was the best for me.

The barrel can be purchased direct from MGM, many configurations are available, with flutes, blued, stainless, stainless with flutes, yada, yada, yada. While it may not be a 358 BFG, a 225gr Nosler @ 2500fps with 1MOA accuracy, really doesn't care what firearm it comes out of.

I got it just because I like exploring new ground. From all I understand, and I have done extensive research on the caliber, the "standard" reamer that MGM uses, makes the wall thickness of the neck right at .014". Using a tool & die makers micrometer, that is just what the thickness of the brass from Just Hunt is giving me.

I have a BUNCH of loads already that exceed the velocity performance that they said, now all I want to do is work on the accuracy aspect. I would like to get sub MOA consistently but am afraid that that has more to do with me than the gun!



Still, like I said above, a 225gr Nosler @ 2500fps give you a really hard impacting round and to add, with a BC of .421, it stands a much better chance of giving it to you a lot further out than other bullets.


FWIW, this is going to be a fun endeavor no matter how you slice it. Generic or not.

 

[fireball168]

I am interested in the 35 gremlin and I guess I figured the 6.5 grendel mags would work with maybe with some feed lip tweaking?

The thing to look for is the depth of the front rib on the magazine, you want it as shallow as possible.

The 6.5 Grendel magazines seem like the obvious choice, but the front ribs are generally in the .115-.120" range.

A few years ago, Alexander got a run of mismade C-Products magazines that were just over .100" deep, they didn't run too bad - but Bill wanted full pop retail for them.

Ideally, somewhere between .058-.072" should be the sweet spot - just haven't found one yet. Modifying Thermold and other polymer magazines hasn't worked well as they all bulge with the fatter case.

Look at this picture,

The top cartridge is above the front rib, looks fine - the Accubond load below it is being pushed inward where the front rib contacts the projectile.

That's THE issue with the Gremlin and currently available magazines.

 

[fireball168]

From all I understand, and I have done extensive research on the caliber, the "standard" reamer that MGM uses, makes the wall thickness of the neck right at .014".

Inspect what you expect.

Find some pin gauges, or make a chamber casting and measure your chamber neck diameter.

Then measure your loaded cartridge case neck.


Brass is expensive, regardless of who you are buying it from - might as well do what you can to maximize its life.

 

[Skip]

Thanks for the input. Will do.

Most of my cases have been fired 5 or 6 times already. I wish there was a neck only sizing die but haven't been able to find one yet. Maybe I need to make my own. We will see.

The firings I have done are probably hotter than most folks are loading. It I have had no primer issues nor case head expansion. They still measure what the did when new. As a matter of fact, I have yet to have what I call a flattened primer with any of my loads.

The powders I have used are a typical lot for the 358 Winchester. I am getting better external ballistics though. At first, with new brass, I was afraid I wasn't going to be able to get enough extruded rifle powder in the case to get the velocity desired.

Since the beginning though, that outlook has changed.

Right now, the gun is giving me MOA with the lighter Hornady bullet, and if I get the chance to take it to the field for deer here in Indiana, I am confident that I can take one out to 200 yards with it. I am getting better than 2600 fps with that bullet.

So, again, I will do more investigation into my particular firearm. Although, I feel confident about what has been stated earlier about it.
H4895 shows some promise but I really like BLC-(2) as well.

There are a few other powders in the "Extreme" line that are showing promise as well.

 

[worksalot]

Fireball 168, I see what you are saying about the ribs. I checked all of the differnt mag that I have and none will work....But now I know what to look for. Thanks and i will start looking .

 

[fireball168]

If you want a couple of pieces of brass - send me your address in a PM.

 

[Skip]

Had some outstanding results with this "generic" MGM barrel today.

I have been trying to get the 225gr Nosler Accubond to shoot well in this rifle and hadn't been having any "luck". Oh, 1MOA but, this cartridge/bullet/rifle combo should be able to beat that!

Well, today, I did just that. Here is a target:

Using H322 and there were no signs of overpressure at all. The numbers across the chrony were astoundingly consistent.

Not sighted in as you can see on the target. I have the 200gr Hornady Interlock SP sighted in with it right now. A friend of mine used it to take a buck at about 140 yards. Quartering away, in on right side, middle of rib cage, exited left shoulder. That round was going about 2600fps. Didn't expand too much either. Kind of surprised.

Oh well, the big thing is that the deer was on the ground!

 

[KB5VYA]

I am looking to build a .358 Gremlin AR. Can someone give me a source for barrels and dies?

 

[Soarmyvet13]

How many grains of powder and what are the bullet weights? I'm starting a 358 gremlin project.

 

[Soarmyvet13]

You can get a barrel from mcgowan and brass from rcc brass. I can't find the dies so I am looking at having a custom set made.