Thinking about doing a small frame wildcat!

[357Max]

Would love some input from those who've done one.

Here's the plan so far:

Small frame Wildcat "224 SpecWar"

​

Target objectives​

• Case capacity 37.3gr
• Run 77gr @2950+fps from 18" barrel @ std max metal mag length 2.290
• 88eldm/90smk @2750 from 18" barrel @2.290​
• Respectable brass life at speeds listed 5x min.
• Reliable feeding
• Good bolt longevity
• Run heavy pills with RL-16, H4350, Vit N550
• Ability to stretch out load length on heavies should metal mags ever be produced for either the LWRC or New Frontier 6.8 receivers. This would also be a plus for bolt gun builds. +50fps to above in 6.8 receivers with metal mags @2.380" coal
• Max pressure 58,700psi

Parent Brass 400Legend

Reamer will be either Manson or JGS, any reason to pick one over the other? I'm thinking this would require 3 reamers. 1 x Finish & 2 die reamers to neck down. Might need 3 steps?? Any advice on this would be appreciated.

Die blanks will be from Newlon

First barrel will be a $138.0 Green Mountain 21" 7T semi finished Blank. Comes chambered for 223W so I'll have to pull the extension & set it back 1 thread.

Considering using a Bartlain 4R 7T from White oak if the first one works out.

Bolt will be 6.8/.224 Valk LWRC. These IMO are the strongest SPC bolt available & currently been abusing one in a 224 Valkyrie.

Thanks to 400L, we will for the first time have Grendel sized brass with a rim rebated to the SPC bolt size. I'm also hopeful the Winchester brass will be pretty decent

I kind of did a similar concept by forming 24 Nosler brass into .224 Valkyrie. The formed Nosler had +1 full grain more capacity than std Valk brass & uses a 223 bolt. Primer pockets have been dying fast (2-3 firings) with the Nosler brass, but I was pushing it pretty hard.

Performance with the formed 24 Nosler has been pretty impressive for it's 32.7 gr capacity.
18" Rock barrel +1" Rifle gas Craddock
H4350 with 88eldm @2.290
27.2gr = 2691 SD 4.2
27.5gr (C) = 2725 SD 4.8

Lever 88eldm @2.290
25.9 = 2724 SD 14.2
26.1 = 2752 SD 7.5

Lever 77RDF @2.238
27.6 x 10 = 2950 SD 8.4 This load is my go to. Shoots .5 - .75 consistently.

Based on the above I think my proposed case shown below will meet the objectives on a better 6.8 bolt. The + 4.5gr capacity should also open the door to some good powders.

Let me know what you all think. Dumb idea or worth the effort?

As an aside I'll be chambering with a slant bed CNC & that's a whole other topic itself.

 

[Constructor]

JGS for carbide reamers if you want them right but if only doing a few barrels HSS will last a while, Clymer or Manson would be fine for HSS reamers.
I think you will need a lot of steps, I normally only neck down .030 at a time. You could use Grendel and 6mm AR dies when you get near those diameters then finish with your custom 224SW die.

 

[Vynz]

Would love some input from those who've done one.

Here's the plan so far:

Small frame Wildcat "224 SpecWar"

​

Target objectives​

• Case capacity 37.3gr
• Run 77gr @2950+fps from 18" barrel @ std max metal mag length 2.290
• 88eldm/90smk @2750 from 18" barrel @2.290​
• Respectable brass life at speeds listed 5x min.
• Reliable feeding
• Good bolt longevity
• Run heavy pills with RL-16, H4350, Vit N550
• Ability to stretch out load length on heavies should metal mags ever be produced for either the LWRC or New Frontier 6.8 receivers. This would also be a plus for bolt gun builds. +50fps to above in 6.8 receivers with metal mags @2.380" coal
• Max pressure 58,700psi

Parent Brass 400Legend
View attachment 8182190

Reamer will be either Manson or JGS, any reason to pick one over the other? I'm thinking this would require 3 reamers. 1 x Finish & 2 die reamers to neck down. Might need 3 steps?? Any advice on this would be appreciated.

Die blanks will be from Newlon

First barrel will be a $138.0 Green Mountain 21" 7T semi finished Blank. Comes chambered for 223W so I'll have to pull the extension & set it back 1 thread.

Considering using a Bartlain 4R 7T from White oak if the first one works out.

Bolt will be 6.8/.224 Valk LWRC. These IMO are the strongest SPC bolt available & currently been abusing one in a 224 Valkyrie.

Thanks to 400L, we will for the first time have Grendel sized brass with a rim rebated to the SPC bolt size. I'm also hopeful the Winchester brass will be pretty decent

I kind of did a similar concept by forming 24 Nosler brass into .224 Valkyrie. The formed Nosler had +1 full grain more capacity than std Valk brass & uses a 223 bolt. Primer pockets have been dying fast (2-3 firings) with the Nosler brass, but I was pushing it pretty hard.

Performance with the formed 24 Nosler has been pretty impressive for it's 32.7 gr capacity.
18" Rock barrel +1" Rifle gas Craddock
H4350 with 88eldm @2.290
27.2gr = 2691 SD 4.2
27.5gr (C) = 2725 SD 4.8

Lever 88eldm @2.290
25.9 = 2724 SD 14.2
26.1 = 2752 SD 7.5

Lever 77RDF @2.238
27.6 x 10 = 2950 SD 8.4 This load is my go to. Shoots .5 - .75 consistently.

Based on the above I think my proposed case shown below will meet the objectives on a better 6.8 bolt. The + 4.5gr capacity should also open the door to some good powders.

Let me know what you all think. Dumb idea or worth the effort?

As an aside I'll be chambering with a slant bed CNC & that's a whole other topic itself.

View attachment 8182352

Your 224Specwar appears to be a fatter case than the 6.8SPC/224VAL. You may be skipping over the perceived Grendel bolt issues just land in the Grendel magazine issues.

The Grendel case width does not work in 6.8SPC Magpul mags; I don’t think your specwar will either.

 

[Constructor]

Your 224Specwar appears to be a fatter case than the 6.8SPC/224VAL. You may be skipping over the perceived Grendel bolt issues just land in the Grendel magazine issues.

The Grendel case width does not work in 6.8SPC Magpul mags; I don’t think your specwar will either.

I agree, I missed the part about using a LWRC set. When those pmags came out I tried them and found with Grendel cases inside they bulge bad enough you have to hammer them into the lower receiver. A 5 or 10rnd mag may work, I was using the 30s.

 

[357Max]

Your 224Specwar appears to be a fatter case than the 6.8SPC/224VAL. You may be skipping over the perceived Grendel bolt issues just land in the Grendel magazine issues.

The Grendel case width does not work in 6.8SPC Magpul mags; I don’t think your specwar will either.

Yep no intent of running this in the Magpul 6.8SPC mags. The 6.8 P mags don't give any advantage in load length over std metal mags anyway. Plenty of 6ARC's and Grendels running fine with Brenton Long load, ASC, & E-lander mags. These all give 2.290. I thought I was clear on that in the objectives. 6.8 receivers IF metal mags are ever available or I make my own.

Honestly I've been frustrated that the 6.8 platform hasn't been fully taken advantage of by anyone. The magwell is stretched both width and length making it an ideal platform for the fat Grendel case. Whats missing is metal mags. I'm amazed this wasn't the obvious 1st attempt at least for a more capable service weapon. The other weak point of coarse was the Grendel type 2 bolt. 400 Legend brass solves that piece.

My thought was to proof test it in std Grendel mags on a std lower. I already have a lower/upper setup for 2.380" using windowed Brenton mags. If all is well I'd then tackle modding a Brenton long load mag to fit a 6.8 receiver. Have a Tig set up for SS welding. If I get that far I'll probably regret not pushing the shoulder farther forward.

The LWRC 6.8 bolt is a significant piece of this puzzle. They designed it for .gov & tested to 10,000 rounds without cleaning or lube. People forget or don't know LWRC did supply Saudi mil with 6.8's. The extractor is a lobster tail with dual springs, but more importantly does not undercut the adjacent lugs. They're also made from some mystery alloy LWRC won't publicly disclose. My guess would be a maraging steel like Vasco or Aermet 100.

 

[Constructor]

LWRC used 9310 to make the bolts, it was a secret for a long time but I found a document Lietner Wise(original owner LWrc) submitted to the army. Several of us have been using 9310 to machine bolts from since 2009. The 6.8 doesn't break bolts like the Grendel, 6mmARC or any cartridge of that diameter. I machined bolts starting 2009 that allowed us to shoot the 6BRX, 6.5BRX, 270AR, 270MSR (.473 dia) at 60K and we never broke a bolt.

 

[bigjake83]

Would love some input from those who've done one.

Here's the plan so far:

Small frame Wildcat "224 SpecWar"

​

Target objectives​

• Case capacity 37.3gr
• Run 77gr @2950+fps from 18" barrel @ std max metal mag length 2.290
• 88eldm/90smk @2750 from 18" barrel @2.290​
• Respectable brass life at speeds listed 5x min.
• Reliable feeding
• Good bolt longevity
• Run heavy pills with RL-16, H4350, Vit N550
• Ability to stretch out load length on heavies should metal mags ever be produced for either the LWRC or New Frontier 6.8 receivers. This would also be a plus for bolt gun builds. +50fps to above in 6.8 receivers with metal mags @2.380" coal
• Max pressure 58,700psi

Parent Brass 400Legend
View attachment 8182190

Reamer will be either Manson or JGS, any reason to pick one over the other? I'm thinking this would require 3 reamers. 1 x Finish & 2 die reamers to neck down. Might need 3 steps?? Any advice on this would be appreciated.

Die blanks will be from Newlon

First barrel will be a $138.0 Green Mountain 21" 7T semi finished Blank. Comes chambered for 223W so I'll have to pull the extension & set it back 1 thread.

Considering using a Bartlain 4R 7T from White oak if the first one works out.

Bolt will be 6.8/.224 Valk LWRC. These IMO are the strongest SPC bolt available & currently been abusing one in a 224 Valkyrie.

Thanks to 400L, we will for the first time have Grendel sized brass with a rim rebated to the SPC bolt size. I'm also hopeful the Winchester brass will be pretty decent

I kind of did a similar concept by forming 24 Nosler brass into .224 Valkyrie. The formed Nosler had +1 full grain more capacity than std Valk brass & uses a 223 bolt. Primer pockets have been dying fast (2-3 firings) with the Nosler brass, but I was pushing it pretty hard.

Performance with the formed 24 Nosler has been pretty impressive for it's 32.7 gr capacity.
18" Rock barrel +1" Rifle gas Craddock
H4350 with 88eldm @2.290
27.2gr = 2691 SD 4.2
27.5gr (C) = 2725 SD 4.8

Lever 88eldm @2.290
25.9 = 2724 SD 14.2
26.1 = 2752 SD 7.5

Lever 77RDF @2.238
27.6 x 10 = 2950 SD 8.4 This load is my go to. Shoots .5 - .75 consistently.

Based on the above I think my proposed case shown below will meet the objectives on a better 6.8 bolt. The + 4.5gr capacity should also open the door to some good powders.

Let me know what you all think. Dumb idea or worth the effort?

As an aside I'll be chambering with a slant bed CNC & that's a whole other topic itself.

View attachment 8182352

Just curious, why a wildcat? And not just step up to a 6CM or 6.5CM??

Just a shits and giggles thing?

 

[Constructor]

I do it for lighter rifles. I have a 6.5 Creed built on DPMS G2 receivers that is a fuzz over 10lbs with a 22" fluted barrel and 30oz Nightforce but I would rather shoot my TAC 6 cat built on AR15 receivers that weighs 8lb 14oz. 95SMks at 2800 do pretty good.

ETA- Around 2006 I necked down a 6.8 slightly shortened to 42mm, it would shoot the 75 Amax at 3000fps out of a 20" Krieger. Later Hornady changed to the 80ELD. Jason Peterson used one with the ELDs to shoot a 4.5" group at 1200yds at Strategic Edge in Tn.

 

[357Max]

Just curious, why a wildcat? And not just step up to a 6CM or 6.5CM??

Just a shits and giggles thing?

I have a Proof steel 24" RL+2 in 6.5 CM on back order. Already have 1 large frame in 308.

I like large and small. This is more just as a challenge for personal satisfaction & the 400 Legend brass is exactly what I'd been wanting, SPC bolt with Grendel body. I want Lever performance, but with good stick powders & decent component life. I know the full Monty right!

These 2 are both fun & sadly they are about equal ballistically. 224 Valkyrie on left slings 88 eldm's @2750 or 77 RDF's @ 2950 from an 18", 6ARC on right will push 109LRHT @ 2700 or 95 VLD's @ 2930 from a 22". That level of performance requires formed 24 Nosler brass in the valk & pockets are good for 3 & done. For both it's only possible with Lever.

To me the Valkyrie is more impressive since it's doing it with an 18" barrel.

 

[357Max]

LWRC used 9310 to make the bolts, it was a secret for a long time but I found a document Lietner Wise(original owner LWrc) submitted to the army. Several of us have been using 9310 to machine bolts from since 2009. The 6.8 doesn't break bolts like the Grendel, 6mmARC or any cartridge of that diameter. I machined bolts starting 2009 that allowed us to shoot the 6BRX, 6.5BRX, 270AR, 270MSR (.473 dia) at 60K and we never broke a bolt.View attachment 8182871

It's just not right to tease me like this. I've been lusting after one of your Titan bolt/extension setups for a while.

Please tell me this is a current picture! That'd be perfect for this project.

I thought Lietner Wise left before they did the 6.8 endurance testing + the Saudi contract? If it's just 9310 that's disappointing, not that there's anything wrong with 9310. Still the extractor cut @ bolt face is a pretty big improvement to the already strong SPC bolt.
Vasco or Aermet 100 would put it in a different league.

I've long been a fan of the Sharps bolts made from S7 with DLC & they finally made SPC and Grendel Type 2.

 

[Constructor]

Yeah there's a box of them in the warehouse somewhere, 750XDs and 800 series too. The Titan bolts are sized for 7.62x39 or have a .124 recess. I'm sure I have some 800 series sized for the 6.8.

 

[357Max]

Yeah there's a box of them in the warehouse somewhere, 750XDs and 800 series too. The Titan bolts are sized for 7.62x39 or have a .124 recess. I'm sure I have some 800 series sized for the 6.8.

Well if you would be willing to part with a set or a few please let me know. Might need a little guidance on sourcing the correct Firing pins and extractors.

This project will take a significant investment so I may not, probably wont, yeah doubt I'll stop at 1.

Gator set True chucks aren't cheap.

 

[Constructor]

Well if you would be willing to part with a set or a few please let me know. Might need a little guidance on sourcing the correct Firing pins and extractors.

This project will take a significant investment so I may not, probably wont, yeah doubt I'll stop at 1.

Gator set True chucks aren't cheap.

For the 6.8 diameter or Grendel?
Those Titan bolts have a .124recess (.442 dia)but if you are making the barrel you can set the headspace however you like it.
Firing pins are standard, extractors come from Black Rifle Arms in New Smyrna Beach.

 

[357Max]

For the 6.8 diameter or Grendel?
Those Titan bolts have a .124recess (.442 dia)but if you are making the barrel you can set the headspace however you like it.
Firing pins are standard, extractors come from Black Rifle Arms in New Smyrna Beach.

For this project a 6.8 diameter, that was your 800 series correct? STD head space on those?

For the hell of it, I just checked Starline and they do have basic Grendel brass available, but it's 1.550" Any idea how much it will grow sizing down to 224? Not sure if it would reach 1.630"?

With the Titan bolt it would be nice to have the extra meat of the Grendel head around the primer pocket.

 

[hlee]

The 224 predator already hits your velocity spec with 77 gr projectiles. It fits in a standard AR receiver, using Grendel mags. Elander Grendel mags suck. ASC run without issue for me.

Wildcatting seems like a lot of effort for something that has already been done.

 

[Constructor]

Some of it is about seeing how good the idea is and knowing you came up with it.
The 224 Predator is a 224 LBC/224AR/224Grendel for all practical purposes. People were putting trademarks on cartridge names so I didn't want to take a chance and use any of them. The cat had already been done but I made batches of $200 barrels so they wouldn't be expensive custom one offs.
One thing that has always hurt the Grendel performance is the thin cases at the bottom. I tried to get starline to change the inside die to beef up the area that was unsupported by the chamber so we could run higher pressure and the cases would last longer. They wanted crazy money to make one run for me like $10,000 for the die and I had to order 100,000 cases. at 32 cents each. I hope the Winchester cases are thicker since a rebated rim is being used.

 

[Constructor]

For this project a 6.8 diameter, that was your 800 series correct? STD head space on those?

For the hell of it, I just checked Starline and they do have basic Grendel brass available, but it's 1.550" Any idea how much it will grow sizing down to 224? Not sure if it would reach 1.630"?

With the Titan bolt it would be nice to have the extra meat of the Grendel head around the primer pocket.

I'll look around, I need to sort all of that stuff out anyway.
If it's good brass, typical of Win 308/243 the primer pocket should should be fine with 6.8 dia, I've been running the 6.8 at 58-60k without problems. I couldn't guess the growth going from .400 to .224. If you can get the brass and you have a bunch of dies you could try to neck a case down using odd dies. I've used pistol dies, the bottom of rifle dies and every thing else to get a test case.

 

[357Max]

I hope the Winchester cases are thicker since a rebated rim is being used.

It's an educated gamble, but they do have the thickest base for the 350 Legend. The Win Legend brass weighs 6gr more than Hornady & it appears to all be in the bottom.

 

[357Max]

I'll look around, I need to sort all of that stuff out anyway.
If it's good brass, typical of Win 308/243 the primer pocket should should be fine with 6.8 dia, I've been running the 6.8 at 58-60k without problems. I couldn't guess the growth going from .400 to .224. If you can get the brass and you have a bunch of dies you could try to neck a case down using odd dies. I've used pistol dies, the bottom of rifle dies and every thing else to get a test case.

Much appreciated, the 800 bolt/extension would be sweet. Not in a big rush. Still have a good bit of work to do getting the machine set up.

I might give it a try with the Starline. Might be possible to do this as a no turn neck since the basic Starline is only .009 at the top.

Already planned on needing to neck turn the formed 400L brass.

 

[hlee]

Some of it is about seeing how good the idea is and knowing you came up with it.
The 224 Predator is a 224 LBC/224AR/224Grendel for all practical purposes. People were putting trademarks on cartridge names so I didn't want to take a chance and use any of them. The cat had already been done but I made batches of $200 barrels so they wouldn't be expensive custom one offs.
One thing that has always hurt the Grendel performance is the thin cases at the bottom. I tried to get starline to change the inside die to beef up the area that was unsupported by the chamber so we could run higher pressure and the cases would last longer. They wanted crazy money to make one run for me like $10,000 for the die and I had to order 100,000 cases. at 32 cents each. I hope the Winchester cases are thicker since a rebated rim is being used.

So far, with an N of one barrel, the limiting factor for brass life in my 224 Pred has been loose primer pockets, not case head separation. But this isn’t about that cartridge, so I’ll bow out.

 

[357Max]

The 224 predator already hits your velocity spec with 77 gr projectiles. It fits in a standard AR receiver, using Grendel mags. Elander Grendel mags suck. ASC run without issue for me.

Wildcatting seems like a lot of effort for something that has already been done.

Like Constructor said for me it's about proofing the idea & the satisfaction of making it happen. It's about passion. I love this hobby. Fills the void left from my former career as a machinist/engine builder. It was soup to nuts meaning I did everything from build specs through dyno testing. Lot of effort yes, but I enjoy that part.

Thanks for the heads up on the Elanders. Hadn't tried them yet. Been running ASC and Brenton's in my 6ARC without issue.
I'll disagree about it's been done part. Similar sure, but never an SPC bolt with a Grendel body. The Specwar case is 1.630 or only .030 longer than a 224 Valkyrie, but with 6gr more capacity. It'll fit in a std receiver set no problem. Part 2 of this project is to cobble together a metal mag for the 6.8 receivers & move it to that platform. This again is just to proof the concept. The wider magwell on the 6.8 receivers should actually be ideal for mag geometry with the Grendel case. +.100 load length within the mag would also be a first AFAIK.

I don't regret changing careers, but it left a hell of a void & this hobby satisfies my desire to work with my hands and create things.

Here is a picture of a wildcat engine part I created & proofed. This was in 2007.
Camshaft dampener. Had ATI build it for me. The Team owner thought I was nuts to add 5lbs to the rotating assembly on a pro-stock. Pick on the dyno showing the raw aluminum lt. wt. cam gear installed. The dampener was good for a solid 9-10 horsepower between 8500-10500. Might not sound like much gain for a 1400hp engine, but 10hp is a big deal on one of these. It also increased valve spring life about 30% were talking like 9 passes instead of 7. Not long after several top NHRA teams started running them as well as NASCAR. I doubt I was the first to come up with the idea & don't care. It was definitely the first ever run on an NHRA Pro Stock.
Got all the reward I needed on the Dyno.

BTW that whole damn engine is a wildcat. The only off the shelf parts were the crankshaft dampener, the Jesel lifters, & some of the ARP hardware. I cherry picked the raw Glidden era Pro Stock block's from a Ford warehouse in Detroit. Flew to LA and modified casting cores at Buddy Bar for a special run of heads, went to Jesel in NJ to map out and 3d print/proof custom rocker bars. There's a whole lot more involved in just those 3 items than anyone here cares to hear about.

Guns aren't that complicated, but they sure are fun.

 

[maddazzshooter]

I do it for lighter rifles. I have a 6.5 Creed built on DPMS G2 receivers that is a fuzz over 10lbs with a 22" fluted barrel and 30oz Nightforce but I would rather shoot my TAC 6 cat built on AR15 receivers that weighs 8lb 14oz. 95SMks at 2800 do pretty good.

ETA- Around 2006 I necked down a 6.8 slightly shortened to 42mm, it would shoot the 75 Amax at 3000fps out of a 20" Krieger. Later Hornady changed to the 80ELD. Jason Peterson used one with the ELDs to shoot a 4.5" group at 1200yds at Strategic Edge in Tn.

it's really good to see people thinking outside the box to create/innovate for the sideliners to criticize without letting it stifle you creativity. This is a hobby of mine as well and I love seeing projects come to fruition.

 

[maddazzshooter]

This is a very expensive hobby for me as I'm not a machinist or gunsmith. I've been loading since 1986 and focused mostly on the ballistics side of loading and only started wildcatting in the last six years...