Wildcat Cartridges

There has been a lot of noise and confusion around the 6.5 Grendel® and the similar cartridges that have sprung up around it. Two have surfaced that bear a closer look. The 6.5 BPC has become “the” bolt action chambering that can safely fire Grendel ammo. The differences in the chamber dimensions are minor; the 6.5 BPC was developed by Jim Borden and Dr. Louis Palmisano, the latter of PPC fame. The newest entry into this race is the 264 LBC-AR™ from Les Bear Custom, as the name implies this

Headstamped brass by Hornady

chambering is optimized for the AR platform. The biggest difference between these variations is that fact that the latter two are open use, in other words, anyone can chamber for them, like any factory cartridge.

Some sources call the BPC and the LBC cartridges “improved”. When you compare the drawings this is improved label is pretty hard to understand. There is little difference aside from the tolerances for case expansion, and the throat design. They do have a 30 degree shoulder verses a 28 degree shoulder on the Grendel, however, this will not provide any noticeable change in ballistics as the volume of the case is virtually unchanged. In fact, 2 degrees is barely outside the tolerance limits that most tool makers offer.

Ammo for the 264 LBC-AR

Black Hills Ammunition has new loads being built exclusively for Les Baer Custom at his request and with his assistance in load development. The .264 LBC-AR is loaded with a 123-grain Hornady A-Max bullet is available exclusively from Les Baer Custom. It’s designed for use in Les Baer Custom rifles as well as rifles of other manufacturers, and will also perform in rifles chambered for the 6.5 Grendel cartridge. The brass is produced by Hornady and head stamped .264 LBC-AR. Naturally this brass could be sized in a 6.5 BPC die and used for rifles so chambered.

Clymer Reamers announced at the 2010 Shot Show in Las Vegas that they would soon be shipping piloted chamber reamers that match up to the “West Coast” pattern.  They are also moving to the screw attachment for these reamers as apposed to the old spring clip style retainers.

Todd Wilms, Owner of Clymer is clearly proud of his products and rightfully so.  When he purchased the company almost five years he set about the work of moving the company to a new facility, rebuilding and replacing machines and in short looking at the entire operation with an eye toward improving the products they make.

Headspace for Ackley Improved cases should be a no-brainer. Ackley set up probably the simplest headspace system for a line of wildcats that any gunsmith ever devised.

Rimless or Rebated Improved Chambers…

Ackley Improved cartridges in this category seem to receive the most abuse at the hands of hobbyists and local gunsmiths who do not understand the proper headspace of Ackley Improved designs. P.O. Ackley did establish specific headspace dimensions for all his Improved case designs. The process is extremely simple and for this reason alone folks seem to think they need to make it more complex. Keep it simple.

The most important innovation that Ackley brought to the “improved” concept was with regard to bottleneck rimless cases. He chose the simplest of mechanical solutions to insuring that his improved cases would safely fire factory loads. He shortened the chamber by .004” (4/1000 of an inch). Because the factory case is then a crush fit between the bolt face and the junction of the neck and shoulder, proper headspace is insured. This is why Ackley prescribes setting the barrel back on such cases. You will note that if you follow these simple guidelines there is no confusion about the headspace measurements for “Ackley Improved” designs in rimless or rebated cases.

Some confusion seems to arise out of this headspace issue. Folks get confuse between the set up for a rimless bottleneck case and a rimmed or belted case when discussing ‘Improved” chamberings. Rimless and rebated cases are the case designs which always require a barrel set back to be properly headspaced. As memtioned in the paragraph above headspace on an Ackley Improved rimless or rebated designs is .004” shorter than standard. The shorter headspace means you have no choice but to set the barrel back if you want correct headspace.

There are special Ackley, go-gauges, they have the same shoulder angle as the parent case but they are shorter. This ingenious method effectively controls headspace with factory cartridges in the new larger, ‘Improved’ chamber. The factory cartridge or parent go-gauge becomes the no-go for the new chamber. This system works because the parent go-gauge is .004” longer than the Ackley gauge, exactly the same as the difference between the parent go-gauge and no-go gauge. Example: 30-06 Ackley Improved go-gauge is used with the standard 30-06 go-gauge as the no-go gauge.

The only place the factory case will touch in the new chamber that matters is the bolt face and the junction of the neck and shoulder on the case. It will actually slightly crush the case shoulder when you close the bolt on the factory round. If you eject such a case unfired you will normally see a shinny area on the shoulder where the case was crushed just a little. This crush fit maintains proper headspace during the fire-forming process.

Chambering an Improved Rimmed Case…

Rimmed cases are the easiest of all Improved or wildcat cases to chamber for. The rim is the headspace control feature on these cases. The rim is trapped between the bolt face and the rim cut in the back of the barrel. So if the rim is headspaced correctly you can have almost any shape of case fire-formed beyond the rim, so long as it will extract. The action of the firearm is not sentient; it does not care what the chamber looks like. So rimmed cases utilize standard headspace gauges for the caliber, no Ackley gauges needed.

There is no need to set the barrel back on a rimmed cartridge when you convert it to an Improved design! Why? Because the rim controls headspace, the fact that the shoulder will be moved forward and the neck shortened has exactly NO effect on headspace. Reamers for improved cases normally have the rim cutter integral to their design. Simply paint the rim cut in the barrel with machinists blue, when the rim cutter gets close to this material just watch close, as soon as it scratches the material, stop reaming. Utilizing this method there is no danger of changing the headspace of the gun in the process of ‘Improving’ the chamber.

Rimmed cases headspace on the rim of the case only, ‘Improved’ cases of the rimmed variety often incorporate a shorter neck, thus the shoulder is moved forward to increase capacity, this is combined with increased shoulder diameter. Often rimmed cases benefit the most from an ‘Improved’ design, simply because they gain a much higher percentage of case capacity.

Chambering an Improved Belted Chamber…

What was said of rimmed cases above is also true of belted cases. Belted designs headspace on the belt much the same way rimmed cases headspace on the rim. The distance between the bolt face and the belt cut in the barrel is the headspace for these cartridges. Like the rimmed designs, ‘Improved’ belted cases use the standard headspace gauges, no Ackley gauges.

While it is possible to use machinist blue as suggested with the rimmed case, you will quickly find that it is much harder to determine if the machinist blue has been scratched, there is simply much less area to view. For this reason it is a good idea to set the barrel back when doing a belted magnum improved case. If the barrel is slick with no sight holes drilled in it you can set it back .004” so that that bolt will not close on the go gauge. Then rechamber with the Improved reamer until the go gauge will allow the bolt to close normally.

One of the objections to wildcatting that I hear from time to time is the cost.  If you had to build a rifle for every caliber you tried out it could be a very expensive proposition.  There is a pretty simple way to cut this cost and allow for many more excursions into the realm of wildcat cartridges.  Today’s switch barrel single shots are a great way to try out that cartridge that you have always been curious about or test out your own design.

There are entire Internet forums devoted to these various single shot rifles and pistols.  One of the biggest is www.go2gbo.com (Gray Beard Outdoors).  The possibilities are limited more by imagination than anything else.  All you do is order in the gun or the barrel you need as the parent for your new caliber.

Now that your thinking about this, just grab a good reloading manual that lists the cartridge your interested in, also “Cartridges of the World” By Frank C. Barnes or “The Handloader’s Manual of Cartridge Conversions” by Donnelly & Towsley are both great sources of cartridge information and dimensions.  Just look up the dimensions for the cartridge you want and compare it to the original chamber dimensions, this will tell you if your project is feasible.  It’s the same process you would use if you were having an old barrel rechambered on a bolt gun or Ruger #1 as well.  Reamer makers will also provide chamber drawings for calibers that are not proprietary.

OK, Shot Show is just a couple of weeks away now.  We will be attending the show and will look for reloading tools, bullets, dies, and of course anything that might be of interest to the wildcatter.

Watch here for updates during the Shot Show. 

In the September-October 1970 Issue of Handloader magazine Ken Waters reported on a “new” cartridge, the 228 Hawk.  This cartridge was developed by R&M Chronograph Service of Selma, CA.  For all intents and purposes the 228 Hawk was little more than a modernized version of the 22 Newton.

The Newton used a .227-.228″ bullet and was based on the 7×57 case.  The whole idea behind the 22 Newton was to use a 90 grain bullet at about 3000 fps for deer class animals.  Many states today do not allow the use of 22 caliber rifle for hunting big game, this is a direct result of Hunters using the wrong bullet (too light) in cartridges designed for 70 to 90 grain bullets.  The caliber list would include 22 Savage Hi-Power, 22 Newton, 228 Hawk, 228 Ackley Magnum, 224 Clark, and 224 TTH.

Newton was limited by the powders available in 1914, he claimed velicities of 3100 fps, this velocity is atainable today with similar cartridges we see 80 grain bullets being pushed at 3550 fps.  Ken Waters found that his particular 228 Hawk rifle would drive a .2275″ 84 grain Schwartz hollow point up to 3200 fps.  Schwartz bullets were custom made by a gunsmith from Michigan by the name of Wayne Schwartz.  Hornady currently makes a 70 grain bullet but it is made for the Savage Hi-Power and will not hold up to the velocity of this hot rod.  Huntington’s is carrying some 60 and 70 grain custom bullets, the too are listed as being made for the Hi-Power. 

Today to take full advantage of the 228 Hawk, the 22 Newton, or the 228 Ackley magnum you would have to make your own bullets.  These hyper velocity cartridges required a tough bullet with a thick jacket.  6mm jackets might be resized for the .228 providing a thicker jacket.

Newton was the first the play with the concept of a large capacity case for a 22 with heavy bullets for deer class hunting.  Guys like Jerry Gebby, and P.O. Ackley followed up on the Newton concept as better powders became available.  The 228 Hawk came on the scene in about 1970, other similar cartridges are the 22-243 Middlestead, 224 Clark, and most recently added to the club is the 224 Texas Trophy Hunter (TTH); the last three are .224 caliber cartridges and with 80 grain bullets and the correct twist can be pretty amazing cartridges.   Do you feel the need for speed!?

The 22 K-Hornet was one of the very first fire-formed “improved” wildacts.  It has stood the test of time in terms of popularity, it is still popular today to punch the chamber out on any 22 Hornet.  It’s low recoil and report make this a popular cartridge for shooter who have to worry about noise. 

Lylse Kilbourn and G.B. Crandall worked together on the Kilbourn designs including the 22 K-Hornet.  Case capacity of the K-Hornet is about 10% greater than the parent case.  Because the original case uses so little powder this improved design is more flexible in loading.  Allowing for the use of a wider variety of bullets and powders.  Of course the greatest asset of the K-Hornet is the ability to fire factory ammo to fire-form new cases.

Of current guns chambered for the 22 Hornet, the 77/22 from Ruger is a great option.  It gives you a bolt action with a removable magazine.  The conversion to this caliber is pretty simple, just bore out the chamber to K-Hornet and then modify the magazine for the fatter cases.  The magazine modification requires two changes, first the steel insert has a shoulder to hold the cases to the rear as the rise to the top of the magazine this must be moved forward to match the fire formed cases.  It can be done on a mill or with a die grinder.  Second the thimble of the magazine must be modified so the flutes will allow the fatter shoulder of the K-Hornet to ride closer to the center.

I was tempted to name this the 358 Bureaucrat but some mid-level functionary might mistake the name for a threat and make life difficult for anyone who owns one.  So since it is designed for Indiana’s special rules I decided on the 358 Indy instead.

The Natural Resources Commission of Indiana revamped thier rules to allow rifles used with specific caliber limitations. 

1. Bullet must be .357 or larger in diameter

2. Minimum case length of 1.16"

3. Maximum case length of 1.625"

Of course this allows for a number of good pistol cartridges to be used in rifles for the Indiana Deer season.  Several clients approached me with the idea of using the WSSM case as a basis for a wildcat that would meet the above criteria.  The result is the 358 Indy, 375 Indy, and 416 Indy.

Case capacity for the 358 is identical to 358 Winchester, the only difference is the used of a much shorter cartridge to adhere to the new Indiana rules.  The ballistics with the same bullet weight are virtually identical for the 358 Indy and the 358 Winchester cartridges.  Any rifle that can be chambered for the WSSM cartridges will work well with the 358 Indy.

This is a great example of a wildcat designed to meet a specific set of criteria.

Here we are a totally new web site just for Wildcaters.  It’s tough enough to be a “gun nut” but if you have the disease bad enough; you become a wildcatter. 

This blog will contain commentary and information about wildcatting, gunsmithing, tools, reloading and much more.  I have contacted many of my acquaintances in the gun trade and many have agreed to be guest bloggers.  That means you will have access to folks who normally would not have time to blog.

Our parent web site, www.wildcatintel.com contains a huge amount of data for wildcatters.  We start off with a data base of cartridge dimensions, we will be adding drawings for each cartridge based on the dimensions so you can visually compare them.   We will continually add articles to our archive, both new and historical, we are always looking for letters and historical documents to add to our archive, so long as they add to the knowledge base for wildcatting.

If you have ideas about where this site should be headed, speak up!