is driven back until it is supported by the bolt, thereby stretching and thinning the (already extremely thin) case body (thinning usually occurs just forward of the solid web).
Most European-made Hornet guns
have very tight headspace. Conversely, many U.S.-made Hornet-chambered guns have very loose headspace. In the latter, stretching can thin the case body
40-GRAIN BERGER HP (MOLY PLATED): 45-GRAIN CASE OAL: 1.925 inches, which exceeds SAAMI maximum 22-Hornet length by 0.205-inch. For loads where length must conform to standard Hornet cartridge length, reduce charges about 1 grain. In the CZ test gun, these loads had 0.020-inch bullet-to-rifling jump with only 0.065-inch seating depth. Longer loads are not feasible.
40-GRAIN HORNADY V-MAX (MOLY PLATED): 45-GRAIN CASE OAL: 1.962 inches, which exceeds SAAMI maximum 22 Hornet length by 0.242-inch. For loads where length must conform to standard Hornet cartridge length, reduce charges about 1.2 grains. These loads had 0.020-inch bullet-to-rifling jump with only 0.065-inch seating depth. Longer loads are not feasible.
40-GRAIN NOSLER BT (MOLY PLATED): 45-GRAIN CASE OAL: 1.955 inches, which exceeds SAAMI maximum 22 Hornet length by 0.235-inch. For loads where length must conform to standard Hornet cartridge length, reduce charges about 1.1 grains. These loads had 0.020-inch bullet-to-rifling jump. Seating these bullets to give between 5/1000- to 20/1000-inch bullet-to-rifling jump gives a shank-seating depth between about 0.075-inch and 0.090-inch. Such seating depth tinkering is feasible and desirable for improved accuracy but such loads can be somewhat fragile and deserve special care in storage, transportation, and handling.
40-GRAIN SIERRA BK (MOLY PLATED): 45-GRAIN CASE OAL: 1.975 inches, which exceeds SAAMI maximum 22-Hornet length by 0.255-inch. For loads where length must conform to standard Hornet cartridge length, reduce charges about 1.2 grains. These loads had 0.020-inch bullet-to-rifling jump with only 0.068-inch seating depth. Longer loads are not feasible.
PROPELLANT TESTED CHARGE
300-MP Lil' Gun
H110
A1680 2400
4227 (C) 13.6 (Berger)
40-GRAIN: BERGER, HORNADY, NOSLER, SIERRA FPS @ 15’
(IN)
STD. ACCURACY COMMENTS DEV.
15.6|15.0 3,291|3,262 20|10 0.8|0.5 None|*14.8 max. 15.0|15.5 3,183|3,250 14|16 1.2|0.8 *14.7 max.|None 3,137|3,176 26|30 1.0|0.4 None|*14.0 max. 3,132|3,125 25|35 1.2|0.4 *14.0 max.|None
14.5 15.3|15.2 3,422|3,438 31|19 0.5|0.9 Reduce all by ½ gr.
15.1|15.2 3,368|3,382 35|26 1.5|0.9 for maximum 2,987|3,007 32|34 0.8|1.7 None|*14.9 max
15.4 13.0 13.6
2,962|2,969 31|47 1.2|0.6 *14.9 max|None 2,908|2,962 25|35 0.3|0.8
2,893|2,858 23|28 1.1|1.1 3,061|3,075 16|17 0.3|0.6 3,035|3,046 5|13 0.6|0.5 3,164
22 0.4 Compare to WSM
The 40 Berger HP shares the same jacket and shape as the 30- and 35-grain Berger HPs, and, therefore, has a good BC. With loads in the 3,400 fps muzzle velocity range, it will carry explosive velocity to about 245 yards.
*The 40 Hornady V-Max is difficult or impossible to load with maximum listed charges of ball-type propellants. Granules are apt to trap between bullet shank and case neck. This bullet has an unusually high BC. Hence, loads in the 3,400 fps muzzle velocity range will carry explosive velocity to about 315 yards.
*The 40 Nosler BT is difficult or impossible to load with maximum listed charges of ball-type propellants. Granules are apt to trap between bullet shank and case neck. This bullet has the highest BC of any feasible Hornet bullet. Loads in the 3,350 fps muzzle velocity range will carry explosive velocity to about 335 yards.
The 40 Sierra BK has a very good BC. Hence, loads in the 3,350 fps muzzle velocity range will carry explosive velocity beyond 275 yards.
Page 174 Winter 2012
so much that separations can occur on the second or third firing — in some guns with some cases and loads, separa- tions can occur on first firing! This also limits accuracy potential because the case is moving around in the chamber and the case head is hammering into the bolt as the bullet is accelerating down the bore. Therefore, in such a poorly chambered gun an accurate Hornet load is something of a miracle. When headspace is an issue, use
of milder (pistol) primers in a gun with a relatively light striker and a modest striker spring, can mitigate case stretch- ing but with anything approaching a full-power loading, significant case stretching is apt to occur, regardless of loading technique or primer choice. This condition is usually easy
to determine: In a conventionally chambered Hornet, if the primer is not protruding from the fired case, almost certainly significant case stretching has occurred. (The M-40 and CZ 527 are exceptions as both test samples have properly tight working headspace. I also am aware that at least some other U.S.-made guns have been headspaced properly.) In a gun with excessive headspace,
improving the chamber to K-Hornet monumentally mitigates this problem because the wider and sharper shoulder of the resulting case is approximately 7.7 times harder to move. However, the case walls are still thin and case capacity is very limited, so the force generated by the striker of any gun with normal bolt- action-like striker energy or the blast from a relatively hot primer can be suf- ficient to drive the case into the chamber hard enough to set the shoulder back. For best results, wherever pos-
sible, always use mild primers with the Hornet case, regardless of propellant type or case design. Standard pistol primers are usually adequate. Because of striker design and energy, primer piercing could occur when using pistol primers in some guns. If that occurs in your gun, use standard (never magnum) rifle primers (the WSR seems to be a good choice). Another mitigation that can help
is to set the bullet hard into the rifling. However, this practice can alter perfor- mance, so approach any such load with due caution. Guns that the manufacturer has
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