6.8SPC-based 6mm Wildcats

H

HogThumper

Member
I have been looking to finish a couple of uppers I have had laying around too long. I was about to go with .20 Practical, but coyotes are really the smallest thing I'm likely to be hunting and I'd really like to be able to have the energy to stretch out on deer and hogs, too. I love my .243 rifle and expect to always have 6mm bullets around, too. I'm not interested in the 6X45mm, I've run the numbers and it just looks a little under where I would like to be energy-wise for maximum range on deer. I've been reading everything that comes up on 6.8SPC-based 6mm wildcats in searches of all of my favorite forums and the internet. Below is what I've been able to compile on various wildcats, but there are a lot of gaps to fill before I could start building and I'm hoping some of y'all that own these calibers can help fill some in. I plan to cross-post this over on 68forums since they seem to have a lot of interest in the calibers, too, so please don't think I'm disregarding your responses if you see the same post over there.

My intentions:
Build a 6mm wildcat based on 6.8SPC brass. I plan a finished barrel length of 22" with twist appropriate to stabilize the heaviest bullets I can feed from a magazine. I believe all of the wildcats listed below are capable of the velocity I'm looking for with only minor variance in maximum effective range on the previously stated game. If 6mm WOA is still supported, and a reamer or print can be acquired, as well as reasonably priced dies, it is the forerunner, so far, but I'm not opposed to a plain, necked-down 6.8 case, either. No fireforming, or minimal change to original case dimensions are preferred.

6mm Hagar: Not truly 6.8SPC-based, but based on the 6.8’s .30 Rem parent case. Easiest to find reamers and dies for.

Reamer: PTG $169.95
Dies: $85 Hornady-$149 Redding
Brass: $325/500

Refs:
http://www.creedmoorsports.com/shop/6mm-HAGAR/
http://www.6mmar.com/6mm_HAGAR.php
http://www.keystoneaccuracy.com/6mmhagarorders.html

6mm DTI: No reloading data found, no dies listed for sale (assume DTI is sole-provider; made by Hornady), no reamers or specs seem to be openly available. DTI says the shoulder is changed to 30 degrees and moved forward. The designer says it is better for light bullets for varmints, whereas the 6mm WOA is better for shooting heavier bullets. 22” barrel recommended for full burn. http://www.dtechuppers.com/ar-15-dti-upper-receivers.html

6mm DTI on left, 6mm WOA on right:
IMG_0901_s.jpg


6mm WOA: 6.8 SPC case with 23 degree shoulder changed to 30 degrees and moved back; no fireforming required. Dies and reloading data only available through White Oak Armament (hopefully, still are). Unknown reamer design or sourcing. No current mention of it anywhere on their site; I emailed to ask if the caliber is still being supported, haven’t heard back, yet, will update when I do.

6mm SPC: I assume a synonym for 6mm-6.8 with the only dimensional change being necking down to 6mm. I have read it is 43mm long and has the original 23 degree shoulder, but can’t confirm this with a reamer print, yet.

6mm-6.8: Unknown specs, though Robert Whitley of 6mmAR.com reports case capacity of 33.2gr water. Reamer available from PTG (I will be requesting reamer print), but no dies. Is this the same as 6mm SPC? http://www.midwayusa.com/product/123745/...=ProductFinding

6mm PDK (Predator Dog Killer): Not looking too good on support for this cartridge. http://www.pdk20.com/6MM-PDK.html
 
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I have the 6 dti. 22" 10 twist. I get 3250 with 75 hps and 3200 with 80 bt and hp, and 3090 with 85 partitions.

I love this cartridge. I will soon build a 6x6.8 to compare.

I got the dies from Mike at dedicated technologies.

Good luck and keep us updated
 
Those are the numbers that impressed me over shooting heavy .223s or even the 6X45mm. Will you be building the 6X6.8 yourself? Once I can get some chamber specs, I'd like to have Manson or Clymer build a reamer for whatever I go with. I just don't like using PTG reamers if I can avoid them, even at some additional cost. Thanks!
 
I've got a 6x6.8 that was built by Ritch Johnson (PM sponsor: Ritch's Precision Guns) and after one season of using it for coyotes I love it. It has a 20" black hole weaponry barrel with a 1-10" twist. My current go-to load for yotes is a 58gr v-max over 8208 going roughly 3450fps. It is probably the best shooting rifle I have right now.

The 6x6.8 is a simple neckdown of the 6.8. I use a Redding Type S busing die to form once fired Federal brass and a hornady 6mm seater die. I really like this cartridge and am planning to work up some loads for 80-100gr bullets as I just drew a NV antelope tag yesterday.

There is a fair amount on information about this round on this forum, black hole weaponry forum and the ar-15 armory forum if your interested in researching more.
 
I second the 6x6.8 that Ritch builds. Ritch has built many rifles for me and currently building me a 264 win mag. The best part about the 6x6.8 is tactical ammunition sells loaded ammo in SSA brass. Mine was a 24" barrel and the factory ammo shot sub half MOA at 200 yards. I also loaded 58 gr Vmax over 8208 and was getting over 3600 fps. It absolutely hammered coyotes.

Best part is you don't have to buy special dies that cost half a weeks wages to load for it.
 
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There is a thread in the reloading form about the dti with a handfull of loads in there. Plus there a some members that have been shooting them for a very long time. As far as the 6mmwoa goes it was designed for heavier bullets and there is not much info on lighter bullets. But they are both super easy to load for. And as far as reamer prints go for both of the one listed you might have a hard time getting them due to them being specific to the builder. The only way that I think you can get one is to have them send you a barrel and bolt. I have a 6mmwoa with a 22in barrel and it pushes 75gr sierra hp's that hammers coyotes and deer with authority. Send John at WOA an email and be patient he does a lot of shooting. But both he an Mike at detech are great guys to deal with.
 
Six5 Gremlin from Harrison Beene of AR15Performance. It's his latest wildcat....well maybe not by now. The idea was to use longer bullets with better BC's and stronger 6.8 bolts. Of course you can use Six8 Pmags if you use the LWRC upper/lower.

Sendit
 
The cartridges do have some commonalities but some individual characteristics. Both plus and minus.

The HAGAR is based on the original 30 Remington. Sole source brass at this time is Hornady who announced they were no longer making the brass according to what I read a few months ago. They may have backed up on that but have not seen it. Dies are OTC so that won’t be an issue. Some sources for finished barrels. It excels at long range shooting with big bullet are usually single loaded. Other lighter bullets can be shot long if you get a special magazine from Creedmoor Sports with the front cut out of a regular magazine and you can do that. Lighter bullets tend to have to jump if you are throated for the big 600+ yard bullets. Velocity is decent but not earth shattering better than the true 6.8 variants. Slight increase in the case capacity and inconsequential velocity gains. Loading data is not hard to find but not plentiful.

The 6 DTI is an improved 6.8. Produced only by DTI. There is a slight case volume increase and consequential velocity increase that while present is not tremendously more than the rest. It uses a 30 degree shoulder blown forward during the first firing after an initial neck down. Built by DTI the barrels shoot very well, Shilen blanks, and Mike Milli does all the work. He is sole source on the Hornady dies. Brass is available all over the place. Load data is available by gleaning the internet and I understand Mike will send along some Quick Load data to get you started.

The 6 WOA is a 6.8 with the shoulder moved back with a 30 degree shoulder decreasing case capacity. A longer neck, the case is not trimmed, for some usage but a resultant mild decrease in speed as compared to the straight 6SPC/6X6.8. On target not enough to cause any concern. Dies are available from WOA. I have not seen a large amount of loading data on the internet. I think WOA got out of making this one but maybe a call would generate some information in that area.

The 6 SPC and the 6X6.8 are basically the same cartridge. They are a simple neck down to 6 MM with the original 23 degree shoulder being maintained. It is the full 43 MM length. It has been around for a long time and has been made up by many ‘smiths. No case trimming is needed. Loading data is on the net and available from some of the fellows that have done a great deal of cartridge development for Black Hole in helping bring it to market commercially for them. It has a huge following here on PM and more every day. Dies are 6.8 SPC Redding or whatever bushing set up you have and the necessary buttons although standard types dies are available from CH4D. Black Hole makes the 6X6.8 barrels up on demand and Ritch Johnson here was the major shaker and mover on cartridge development with me chipping in a few tidbits along the way.

The PDK is an improved 6.8 SPC using a 30 degree shoulder angle. Not appreciably different than the 6 DTI with only a slight variation in the shoulder placement. Once again a minimal case capacity increase. The loading data available on the website is, to put it mildly, a bit hot. Some of it is doable but others are problematic in that case capacity is below powder charges stated. Also the numbers being put up are in a bolt gun so that does put a different twist to it. Case life might be an an issue at published levels. Dies I would guess are available from the originator of the cartridge.

So in commonalities all but the Creedmoor use basic 6.8 brass. All but the 6 SPC and 6X6.8 require dies from the originators and cannot be loaded with standard dies through bushing changes. I’ve checked with Hornady on all the rest and the only ones they would sell directly to me were the Creedmoor all other needs were referred to the designers.

Reamers for all but the 6X6.8 and Creedmoor are not easily available/ Of course the production of Go/NO GO gauges is also a custom basis vs the 6 SPC/6X6.8 being commonly sourced from any of the usual suppliers like Brownells. Maybe $250 wil get you into a custom set of reamers and HS gauges.

Bullet choices go from the base 50 up to some 95’s at magazine length. All will be devastating. On target a comfortable 600 yards but in the good conditions 1000 is not out of the question. Bullet choices cover all the bases with one antelope meeting a 90 Berger at 646 yards a few year ago that is now hanging on a young man’s wall up in Utah.

Keep us posted as you kick this around. It’s always fascinating to see how decisions are made when we get the AH HA!!!! urge to make something up off the beaten track.

Greg
 
I am on my 2nd 6x6.8. 1st was on a AR15 frame, my current is on a Savage action.
There is no difference in the 6mm sps & 6x6.8.
Dies are easy via redding (bushing) & CH4D (regular set)
Barrels are easily found at BHW and are very accurate.
Loading data is easy to get/find. I have done pretty extensive testing, chrony runs, various powders and loading data for it as well. I posted that up a while back.
IMO there is not a lot of difference with the 6mm DTI & 6x6.8 to even be concerned about.
I have no issues at 700 yards with a 55g or 95g bullet.
It has replaced my .243.
 
Thank you all for the input; Greg, I especially appreciate your time to go into detail. As I am looking for something I can find reamers and dies for easily, it sounds like the 6 SPC/6X6.8 is the route I should go. Going this route makes the most sense. I have to change my power setup in my shop before I can run the new lathe, and with my real job, it may not be until Fall that I turn my next barrel. I'm planning to build this with a Shilen unturned blank as my starting point. Thanks, again, for all of the helpful responses...got everything answered before I even got my membership approved to be able to post the question on 68forums. Now to get a reamer print and see if I can talk Manson or Clymer into making it.
 
Sounds like a great plan. If you hit a snag I'm sure plenty of guys will step up here for an assist. The cartridge variation just wants to shoot and you can buy factory ammuntion for it.

Greg
 
So let me get this straight. You want a reamer print from a reamer I designed. And you want to give said print to another reamer manufacturer to make you a reamer? Don't you feel that's a little unethical?
If your really willing to go to that extreme, why don't you just do it the same way I did. Sit down, design the reamer and build a test barrel. After you go through the process of turning barrels and shooting ( the forth reamer was the design we settled on ) you will have what went into our present design. It also only required about 5000 rounds of ammunition and a half a dozen strain gauges to get us to where we could GIVE you the information you are looking for.
So ask yourself again, is this really ethical?
 
Ritch,
I apologize for offending you. I thought I had made my intentions clear prior to you posting.

Originally Posted By: HogThumperOnce I can get some chamber specs, I'd like to have Manson or Clymer build a reamer for whatever I go with. I just don't like using PTG reamers if I can avoid them, even at some additional cost.

I have not had good experiences with PTG reamers and worse experiences with their customer service. If I could be confident that their reamer would perform, or I would hear back from them in response to a problem, I'd gladly plop my $135 down for the reamer from MidwayUSA and be set. But $135 for a reamer that is bad is less of a problem than finding out after I get a bad chamber. I had no intention to mislead or deceive. I am just looking to build a rifle with what looks like a good caliber. I didn't figure on having the privilege of input from the cartridge designer, but I would figure that expansion of its use would outweigh a brand loyalty. If my use of your design in the manner I intended offends you, I'll be glad to just ask one of my preferred reamer makers to take their 6.8 reamer and change the neck to .273" and call it something else. Like I said, I had no intention of being underhanded, I just want to build something with the tools I have confidence in.

http://www.bbb.org/alaskaoregonwesternwa...ty-or-22598989/

http://www.yelp.com/biz/pacific-tool-and-gauge-inc-white-city
 
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Originally Posted By: 3DHUSKERJust looked at CH4D for dies and I see none. Am I missing something here?


They are not listed. Calling them is the best way to order from CH4D
 
As Ritch said they are not a listed item. Ask for the 6MM Remington SPC. Last I heard they had some on the shelf. Quite a few guys are using them.

They also stock the 25X45 Sharps also that I will be ordering up soon. Ritch has my barrel and I just need to send him the rest of the upper and then I'll be in business.

Greg
 
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