More Questions And Answers Robert A. Rinker
who know about my interest in ballis- tics. Following are a few I have received recently that I believe will be interesting to readers of The Varmint Hunter Maga- zine®. (And limited to the ones where I know the answer.) Question from California: I have
S
recently been in an argument about which shoots harder, a bolt-action rifl e or an automatic and with a shotgun, a pump or an automatic. Answer: First we should agree on
some terms. I suppose you intended to write semiautomatic. Automatic is a type of fi rearm that will feed and load cartridges, fi re and then eject the case and continue as long as the trigger is depressed and cartridges are in the magazine. Many semiautomatic fi re- arms are incorrectly called automatics. A semiautomatic is a fi rearm that
is self-loading but will fi re only one time when the trigger is pulled. Hold- ing back the trigger will not fi re another cartridge. The trigger would have to be released and pulled again. In the gas-operated rifl e, a very
small amount of gas is taken from the barrel to operate a piston, which actu- ates the breech mechanism. While it is true that this will reduce the gas pres- sure, it is such a tiny amount that it can be overlooked. Both a pump and semiautomatic
shotgun are fi red from a closed breech; therefore, there is no difference in ve- locity or pressure, if everything else is equal. In both types of actions, the shot charge will have left the barrel before the breech has begun to unlock. Neither system will have a loss of pressure other than what is normal. Pressure, as used in fi rearm bal-
listics, is the thrust of the gas (force) created by igniting the powder charge. This thrust is against the interior of the case, the chamber, base of the bullet, etc. Safe pressure can vary from 5,000 psi for a black powder gun and 15,000 psi for a .38 Special revolver to 54,000 psi for a .270 Winchester rifl e and 55,000 psi. in a .22-250 Remington rifl e. All are aver-
Page 120 July — September 2011
ometimes I receive questions from readers and other people
ages and the .22-250 is not the highest, but is darn close. Question from a gentleman in
Kentucky: Could you give me some pointers and instructions on how to refi nish a rifl e stock, or add fi nish to a new stock?
Answer: First, let me say that I am
not the best person to seek an answer from as I have spent much of my life doing metal work, and I don’t care for woodwork. Having said that, I recently refi nished a new stock that I put on a lifter-action Parker shotgun that was made during their fi rst year in business. (Yes, I know that you shouldn’t replace the stock on a rare Parker, but this was a gun I purchased at an auction. It had perfect metal and a badly broken stock.) First, I have several books on
gunsmithing, and I looked at each and picked the one that had the best infor- mation on stock work. If you don’t have a good gunsmithing manual, I suggest you purchase one. You can order one from Brownells or
Amazon.com with- out leaving your home. Of course there are other sources, but these are the two that come to mind as this is written. I have made purchases from both sources with success. One thing I learned from my re-
cent experience is it takes time to do a good job. The sanding alone took hours as I worked my way down to very fi ne sandpaper that would leave a glass smooth fi nish. I used Birchwood Casey Tru-Oil
Stock Finish and just followed the di- rections on the bottle, along with the comments and hints in the gunsmithing book. Of course, there are many other fi nishes available from Brownells and other supply companies. Some people like to use just ordinary linseed oil, but I understand it is very time consuming and tedious. In these modern times, you can even purchase a spray-on fi nish. There also are products for spruc-
ing up an old stock without removing the old fi nish and adding a new one. I tried one such product many years ago and was not happy with it. I’m sorry, but I cannot mention the product’s
name, as I don’t recall it. I realize that this is not too helpful,
but as I mentioned earlier, purchase a good gunsmith book and follow the advice therein. Most books devote an entire chapter, and in some cases, two or more, to just stock fi nishing. Good luck, and I wish you a lot of patience. You will need it. Question from Chicago: Several
of us have been arguing about bluing a rifl e barrel. Does bluing inside the bore affect the accuracy? Answer: No. How is that for a
short answer? Sometimes a newly blued barrel will pick up fouling for the fi rst few shots, but a brass bristle brush drawn through the bore will clean it out and it should not occur again. The fi rst few bullets fi red will either remove the bluing or smooth it down. It is very thin and not up to the heat and friction of fi ring. If a freshly blued barrel tends to not be as accurate as before bluing, I would look elsewhere for the problem. Question by email: I want to cut
off some of the barrel of my Winchester Model 70, but I do not want to hurt the performance. How much can I remove and can I do it without a lathe. I am a retired tool and die maker, so I can do metal working. Answer: First we must remember
that any rifl e barrel cut below 18 inches is illegal under Federal law, unless it is registered under the Federal fi rearms act. Also, anything under about 20 inch- es will have a very unpleasant muzzle blast. Of course, that is just my opinion, and you may not be bothered by it. Back in ancient times, I served a
tool and die apprenticeship at a large national corporation that also sent me to engineering college. You will have no trouble getting the end square. Just remember to do something about the bore at the muzzle so it is smooth and has nothing that will affect the accuracy. Some chamfering and lapping will do wonders.
Now, let’s look at some of the technical aspects of barrel length. Barrel length is an important fac- tor in bullet effi ciency as it relates to
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