577 TYRANNOSAUR

The following data was developed in an A-SQUARE Hannibal model rifle. The rifle weighed 13.6 pounds. No effort was made to shoot it for group accuracy, as the whole purpose of this rifle is as a last resort stopper for animals that are intent on changing the make up of your anatomy! Suffice to say that all groups with all powder charges, at various velocities, went into a group of approximately 8 inches, at 100 yards, with the majority of the higher velocity loads grouping in less than 3 inches! This is fantastic accuracy for a rifle of this power, with open sights.

We could not approach the published velocities in the excellent A-SQUARE reloading manual, with their listed powders. As an example, they listed 177.5 grains of Reloader 19 for a velocity of 2473 fps. We used 178 grains of our lot of Reloader 19 and only managed to get 2283 fps. That is almost 200 fps less! Their data was apparently developed in a barrel of 26 inches, while ours measured only 23 inches. Still, this is no criticism of A-SQUARE, it just shows the differences you might get by using different rifles and different lots of powder. In the velocity department, we were able to increase the velocity to over 100 fps more than the maximum published by A-SQUARE, by using a powder they did not use. There was no sign of excessive pressure at all, in fact, we think that 2600 fps is quite feasible in this rifle without too much trouble except recoil! We only stopped because we ran out of bullets!

And talking of recoil, this rifle has is it in spades! Admittedly, it is fitted with the A-SQUARE Coil-Check stock, which has three mercury reducers and the pad area is significantly larger than a normal stock. Both of these modifications to the stock will help reduce recoil. Still, any cartridge that produces over 11,000 foot pounds of energy is going to give you a good whalop. And I guarantee you, you are not going to be disappointed!

Credit must be given to A-SQUARE for designing and bringing out a number of very high velocity cartridges in their caliber, like the 300 PEGASUS and the 338 EXCALIBUR. Also they produce factory ammo for many wildcats and old cartridges. We have one of their HANNIBAL rifles in 300 PEGASUS here for load development. As soon as our testing is complete, we will put it up on the site.

I have a Ruger #1 rechambered for the 460 Weatherby magnum, and a Dakota 76 custom rifle chambered for a wildcat cartridge based on the 416 Rigby case necked up to 475. The recoil of the 577 Tyrannosaur at velocities of 2150 fps and below is comparable to the above mentioned rifles. Once the velocity gets to 2400 fps, then the recoil is very severe. And at our maximum of 2581 fps, it is plain painful!

Personally, I would take my chances with a charging elephant or buffalo armed with a 460 Weatherby magnum, or even a lesser cartridge like the 375 H&H magnum, rather than the 577 Tyrannosaur. I know I would be scared of the recoil! Also, please bare in mind that WHERE you place the bullet is more important than the SIZE of the bullet! I have shot a number of elephants, and dozens of cape buffalo. Most of them with a 375 caliber wildcat based on the 404 Jeffery. The majority of them are one shot kills, and according to my professional hunter, with over 30 years of guiding, they do not seem to go any further than when shot with larger caliber rifles.

We have a HEYM bolt action rifle chambered for the 600 Nitro Express cartridge. We are still waiting for our supply of bullets, and as soon as we get them, we will try to develop some loads for it. It would be interesting to see this cartridge performs in a bolt action rifle.

We used the Federal 215 primer, and the Barnes monolithic solid 750 grain bullet, and the overall cartridge length was 3.710 inches.

POWDER AND CHARGE

VELOCITY

ENERGY

     

160 H4350

2001

6670

160 RELOADER 19

2017

6780

165

2080

7210

175

2237

8840

178

2283

8680

150 VVN 550

2119

7480

155

2183

7940

160

2204

8090

165

2292

8750

168

2335

9080

171

2392

9540

174

2430

9840

177

2471

10170

179

2501

10420

180

2518

10560

182

2535

10700

184

2554

10870

186

2581

11100

The following data was supplied by my friend Mitch Carter, It was developed in a custom rifle built on a BRNO BBK-02 action, and had a 26" Pac-Nor barrel, KDF muzzle brake and an MPI synthetic stock, fitted with an Answer System Recoil Pad. The rifle weighs 14.3 pounds, complete with a 6X Leupold scope. A-Square brass and the Federal 215 primers were used.

POWDER

VELOCITY

ENERGY

BULLET

 

 

 

 

186 REL 19

2373

8130

650 WOODLEIGH

171 IMR 4350

2429

8520

 

175

2482

8890

 

185 H 4831

2469

8800

 

187

2484

8900

 

189

2503

9040

 

191

2517

9150

 

193

2539

9300

 

195

2584

9640

 

197

2591

9690

 

200

2629

9980

 

 

 

 

 

180 VVN 560

2284

8690

750 WOODLEIGH

182.5

2327

9020

 

184.5

2351

9210

 

180 H 4831

2267

8560

 

185

2384

9470

 

186 VVN 560

2446

9970

750 NAVAL ORDINANCE

188

2453

10020

 

190

2470

10160

 

192

2492

10340

 

194

2534

10700

 

196

2560

10920

 

197

2574

11040

 

198

2608

11330

 

177.5 REL 19

2373

9380

750 BARNES SP

180

2409

9670

 

182 REL 22

2371

9360

750 NAVAL ORDINANCE

183

2390

9515

 

184

2404

9630

 

185

2418

9740

 

183.5

2392

9530

750 BARNES SP

184.5

2408

9660

 

186 IMR 7828

2446

9970

 

160.5 H 4831

2104

7370

750 BARNES SUPER SOLID

 

 

 

 

155 H 4831

1841

6770

900 WOODLEIGH

157

1918

7350

 

159

1951

7610

 

161

2024

8190

 

163

2072

8580

 

165

2109

8890

 

167

2132

9090

 

169

2154

9270

 

171

2179

9490

 

173

2202

9690

 

166 REL 25

1912

7330

 

168

1944

7550

 

170

1971

7770

 

 

 

 

 

 

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  Last updated March 22ND, 2001