GNR Wildcat Cartridges

Here are some of our newer cartridges and some others for comparison. From left to right...

256 GNR..this is a cartridge we developed for use in the Ruger Maximum stretch frame revolver. We have had large 450 pound wild hogs taken with this along with large deer. A great little cartridge and no recoil. Basically a 357 Maximum case necked to 25 caliber. Loading dies and data are available.

Our new 429 GNR. This holds one third more powder than the 44 magnum. A very powerful cartridge with no more recoil than the 44 magnum. Basically a 454 case necked down to 44. Loading dies and data are available.

Next is the 44 magnum for comparison to the 429 GNR.

Next is the 45 Long Colt for comparison to our next cartridge.

This is the new 455 GNR. Compare it to the 45 long colt to it's left. Much more powder capacity. It will equal the 454 with considerably less recoil. Basically a 475 Linebaugh case necked to 45. Dies and data are available.

This next cartridge is not a new one but new for revolvers. It is our 375 GNR. It is chambered in the stretch frame Ruger Maximum revolver. Makes a great big game long range cartridge/revolver combo. Great for elk size critters. Basically a 445 Super mag case necked down to 375. Dies and data are available.

This our new 440 GNR Magnum. This one is chambered in the Encore and in Marlin 1895 rifles plus Ruger #1 rifles. It is for the big game hunter who likes the 44 caliber bullet. Considerably more power than the 444 and nearly as much as the 458 Win. Magnum. Basically it is the 50 Alaskan case necked down to 44 caliber. Dies and data are available.

Now we get into our really big cartridges. This is our new 586 GNR. This big mutha shoots a 550 grain bullet at almost 2000 fps. It is a 577 Snider case with a slight shoulder on it. This one is built on the Ruger #1 rifle. Dies and data are available.

Now the biggest of them all, our new 610 GNR. This monster killer is based on the 577 Snider case, which is readily available, necked up straight to .620 caliber. It shoots a 550 grain bullet at 1900 fps. More power than the 460 Weatherby cartridge but the recoil of a 12 gauge magnum shotgun. This one is chambered in the Ruger #1 rifle. Dies and data are available.

Also remember most of the above cartridges are available as loaded ammo from Cartridge Performance Engineering. They are found on the Links page on this web site. Brass is also available.

Over the past several years we have come out with a few new cartridges that are based on the 405 case. Some of these are older cartridges while some are new. Left to right, they are...

The new 257 GNR. This is a great long range, very flat shooting cartridge for deer and antelope. The 257 GNR case holds approximately 16% more powder than the 25-06 so the cartridge is ideal for those long range shots. It is the 405 case necked down to 25 caliber. Dies and data are available.

This is our new 280 GNR cartridge. We recently did the testing on this one is Africa on 350 pound to 500 pound animals and it took them with one shot in every case. Basically it is the 405 case necked to 7mm. This one equals the 280 Ackley Improved. Dies and data are available.

This is our 310 GNR and probably the most versatile cartridge in this series. It is basically the 405 case necked down to .308. With more case capacity it will easily equal and beat the 30-06 and come very close to the 300 Winchester magnum. Great for groundhogs to bull elk. Dies and data are available.

This is another of our new cartridges, the 8mm GNR Magnum. This is one for those that like the 8mm bullet and need a bit heavier bullet than is available in the .308 caliber. Basically it is a 405 case necked to 8mm. A great big game cartridge. Dies and data are available.

This is our 338 GNR caliber. This one has been around for many years and every year it has been used successfully in Africa, Australia and all over the world. basically a 405 case necked to 338. A great big game cartridge capable of taking anything on the North American Continent. Dies and data are available.

This next cartridge is our 350 GNR, a cartridge that has been around for over 15 years. This one is the 405 case necked down to 35 caliber. It will beat the 35 Whelen and is great for any animal on this continent. Excellent big game cartridge. Dies and data are available.

This is our most popular encore cartridge. It is the 378 GNR, the most powerful 375 caliber wildcat cartridge going, second only to the 375 H&H and runs just barely under the 375 H&H. This one has taken many elephant and dozens of Cape Buffalo. The perfect large dangerous game cartridge. It is the 405 case necked to 375. Dies and data are available.

Also remember any of the above cartridges are available as loaded ammo from Cartridge Performance Engineering. You can find them on the Links page on this web site. Brass is also available.

Over the past couple of years we have come up with several new custom cartridges, bringing the total to over 20 of our own wildcat cartridges. Many of these have been around since the late 70's and early 80s and have been shown on our web site and brochures since then. Some though have not and this seemed a good time to go over the list for those of you that are asking about them.

224 GNR
At the bottom of the our list is the 224 GNR. This varmint cartridge is simply a 357 Maximum necked down to 224. The velocities will run right along with the 222. Intended for the Contender, it is also available in our stretch frame revolver.

7 GNR
Next up is our 7 GNR, one of our most popular and easiest to make. This one is formed by shooting 7X30 in it's chamber. The 7 GNR was not intended as an improvement on the 7X30 as it was developed 2 years before the 7X30 came out. In fact we used 375 Winchester brass when we first developed it. The 7 GNR will almost match the 7mm Mauser when shot in 15 inch or longer. In a 14 inch Contender it will do an honest 2600 fps with a 130 gr. bullet. Great for deer-sized critters and great at long range. Any 7X30 Contender can be rechambered to 7 GNR.

280 GNR
This is our newest cartridge, the 280 GNR Magnum. This cartridge puts a 140 grain 7mm bullet at an easy 2800 fps. A great new cartridge for long range deer and antelope. Based on the 405 brass, this one was developed for the Encore handgun but works even better in the encore rifle. In the 24 inch Encore barrel, this one will almost match the 7mm Magnum. Dies and brass are readily available.

300 GNR

A new-comer is our 300 GNR. This one is simply a shortened 30-30 and intended for revolver use. We took the old 30 Herrett and shortened it 1/10 of an inch and made the case a bit straighter and the shoulder a bit sharper. This one will put a 110 gr. JHP out of a 7 inch barrel at 2200. No set back problems with this one either. Can be rechambered from a 30 Carbine Ruger.

30 GNR

Next up is a virtual duplicate of the 7 GNR except it is in 30 caliber. The 30 GNR is an improvement over the 30-30 Improved. It is formed by shooting the 30-30 in it's chamber. Equla to the 300 Savage, it is great on deer-sized critters. Any 30-30 Contender can be rechambered to this cartridge.

310 GNR
One of our new cartridges developed in 2005, this is the 310 GNR Magnum. Ballistically between the 300 H&H and the 300 Winchester magnum, this one was intended for large game up to elk and excels at this. Extreme long range handgun shots are now possible with the new 310 GNR. and even longer shots are possible with the Encore rifle. Based on the 405 brass, dies, brass and loaded ammo is readily available.

8mm GNR
This is our new 8mm GNR Magnum. This cartridge was developed in 2005 and is a great long range big game cartridge. Elk or moose would be some of the game this cartridge was developed for. Based on the 405 case, dies, and brass are available. This cartridge was developed for use in the Encore handgun but works even better in the Encore rifle.

338 GNR

Now we get into the big game cartridges. The 338 GNR is one of my favorite. I've used this one countless times in Africa and in Australia on 600 to 800 pound critters. In Australia the feral donkeys, which are the size of a large mule, fall to one shot almost every time. It is formed from 405 Winchester brass by simply necking it down. This one will put a 210 gr. bullet our at 2400 fps. The 260 gr. Partition does extremely well on elk size critters.

350 GNR

Built on the same 405 brass is our 350 GNR. This one is necked down to 358 and is a virtual duplicate of the 338 GNR except in 35 caliber. Good for elk size game.

356 GNR

Next up is a fairly new cartridge and one that is very popular. This one is our 356 GNR and is a 41 Magnum case necked down to 357. (note standard 357 for comparison) It is intended for revolvers but works well in Contenders also. It will put a 125 gr. bullet out at 2200 fps. Best when rechambered from 357 Mag Blackhawks, Redhawks, or S&W Model 27 or 28.

358 GNR
Next up the ladder is our 358 GNR. This one is intended for big game and has taken a lot of it through the years. It is a 445 SuperMag necked down to 358 and comes very close to 35 Remington ballistics. Does well in stretch frame revolvers and in Contenders. Any 357 Mag or 357 Maximum Contender can be rechambered.

375 GNR
Our 375 GNR is next in line and this one was intended for the Contender and for stretch frame revolvers. It is formed by necking down the 445 SuperMag to 375. It will pretty much duplicate the ballistics of a 375 Winchester in a Contender. Works great with 225 gr. LBT bullets from Cast Performance.

375 GNR #2
Up next and still in the 375 caliber category is the 375GNR #2. This one is a ballistic duplicate of the 378 GNR but is made on the 45-70 brass. Recommended for Encores only as it has a bit more pressure than the 378 GNR.

378 GNR

Back to the 405 Winchester case for the last of the 3 cartridges built on that case, our 378 GNR. This one is for big and dangerous game. It will put a 300 gr. bullet out of a 15 inch barrel at 2100 fps. Several elephant and numerous cape buffs have gone down to this cartridge.

41 GNR

The oldest of our custom cartridges is our 41 GNR - the 2nd cartridge from the left. (the two n the right are the 410 GNR - see below) This one developed back in 1979 and released it in 1980. It is a 44 Magnum necked down to 41. This one put a 170 gr. Sierra JHP out of an 8 inch barrel at 2100 fps. Everything up to elk and caribou have been taken with this one. Any 41 Mag revolver can be rechambered to the 41 GNR.

41 GNR #2

The second of our 41 caliber wildcats is our 41 GNR #2. This one is a 445 SuperMag case necked down to 41 and has taken a lot of large elk size game through the years. This one will put a 220 gr. bullet out at 2000 fps. This one is best in a Contender or a stretch frame revolver.

410 GNR

The 3rd of our 41 caliber wildcats is our new 410 GNR - the 2 cartridges on the right. This one took 4 large buffalo in a 5 month period. One American Bison and Cape Buffalo. 3 of the 4 were taken with one shot each with the Cast Performance 255 gr. LBT. This is a 454 Casull case neck down to 41. It puts a 255 gr. LBT bullet out at 1900 fps and does best in a 5 shot revolver or Encore barrel.

416 GNR

Still in the 41 caliber but a bit larger is our 416 GNR. ( It is on the left with a fireformed cartridge in the center. The cartridge on the right is 450 GNR - see blow) This one is form from 348 case full length necked up to 416. I have used this one considerably in Africa on large game. It puts a 350 gr. bullet out at 2300 fps and is best in an Encore.

450 GNR

Next in the Dangerous Game category is our 450 GNR. We developed this one back in 1991 for a safari scheduled in Africa the next year. It has repeatedly taken Cape Buffalo and at least 4 elephant that I know of. It is about 5% under the 458 Win Mag and does best in the Encore. This one is a 348 case necked up to 458.

450 KNR
Dangerous Game cartridges are next and the best of that league is our 450 KNR. This one was developed by my son Kase back in '91 and is a 470 Nitro case necked down to 458. It is a real thumper on both ends. Mainly rechambered in Ruger #1 rifles from a 45-70, it is now popular in the Encore handgun and is a real handful.

475 GNR

Next up is our 475 GNR. (compared to a .475 Llinebaugh) This one we developed back in 1987 for the Contender. It is a 45-70 blown out straight and with a 475 caliber bullet seated in it. It puts a 430 gr. LBT bullet out at 2000 fps and has been used extremely well on Cape Buffalo, Bison, and Australian Buffalo. Best in the Encore or in a Marlin 1895 rifle rebarreled. Brass is available.

476 GNR

This 375 grain LBT went thru 4 hindquarters of a large range bull. It went thru hip to hip on one bull hanging and then on to the second bull and thru both hips on that one and then hung up in a pile of fresh hides. It expanded to almost the size of a quarter. Both bulls were probably 650 to 700 pounds, so it went thru a measured 7 feet of meat and bone and 2 inches of stacked fresh hides.

510 GNR

Our newst is also our biggest, the 510 GNR. It is in the center with a .50 Special on the left and .500 Linebaugh on the right. A true 510 caliber, this cartridge is 1/10 of an inch shorter than the 500 Linebaugh and brass is available. It can be loaded up to the 500 Linebaugh or loaded down to the 50 Special ballistics. Best in a 5 shot revolver.

Dies for all the above cartridges are available from us. Loading data is enclosed with the dies.