best-known versions are the Ackley, Weatherby Rocket, and the Kilbourn. They share traits of mechanical advan- tage, extract better, and cases last longer for the handloader. Again, better ballis- tics can be obtained over the standard case by the use of slow burning powder and heavy bullets. 224 ClArk


Timothy Clark of Madera, Califor-


nia, designed this case for long-range use featuring flatter trajectory and harder hitting with greater retained bullet energy. The case is a 257 Roberts necked down to .224" with a steeper shoulder angle and expanded body. The 257 Roberts cases were found to be stronger compared with reforming 6mm Remington brass. The small bore, relatively large case capacity, and ve- locities ranging from 3,800 fps to 4,100 fps can be a combination for short barrel life. Twist rates of 1:9" or 1:8" should be used to stabilize the long, heavy bullets. 22-284


This variation of the 284 Win-


chester case is simply necked down to .224" One way to accomplish this is with a 6mm-284 forming die, then a 22-284 full-length die. The 35-degree shoulder and body taper remain unchanged. We have arrived at the case capacity of di- minishing returns where larger amounts of powder don’t necessarily result in greater percentages of increased veloc- ity. Accuracy will be best with heavier bullets, as several conversations with gunsmiths have resulted in a preference for fast twist barrels and 70-grain bul- lets or heavier. Reported velocities have been in the 3,800 fps range. In closing, there are several oth-


ers not mentioned here, such as the 224 Vais and 22-6mm. A look through Volumes 1 and 2 of Ackley’s Handbook for Shooters and Reloaders reveals quite a few and provides good insight on ballistics. Pressures can spike quickly with overbores, so a careful eye should be kept on fired cases, along with sticky bolt lift. There is abundant information on these cartridges and with a little re- search you will be well-informed on any specific cartridge. If this small sampling finds you wanting more, as it did for me, grab your computer, some books, and brew up a pot of coffee! Soon you will be chambering for that Overbore Addiction.


www.varminthunter.org Page 93


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212