724wd Posted November 23, 2005 Report Share Posted November 23, 2005 ok, on my newly returned 30/06, the firing pin protrusion was .045, so i looked through the other firing pins that i had and found one that was long enough, but it measures .070-.075. anyone have a favorite no lathe way to shorten these little buggers? just start filing it off, keeping the tip round? Link to comment Share on other sites More sharing options...
gunnutty Posted November 23, 2005 Report Share Posted November 23, 2005 I've never tried, but I wonder if mounting it in a drill press would be "true" enough to be fairly accurate. I'd file it to overall length in a vise and chuck it in the press to put the round on it. Maybe it's a disaster waiting to happen... Link to comment Share on other sites More sharing options...
BobVZ Posted November 23, 2005 Report Share Posted November 23, 2005 If we are talking a round firing pin, here's what I do. You can file or grind the tip flat to within a few thousandths of the correct length. Then, chuck the rear of the pin in a hand drill. Attach some 220 grit silicon carbide paper to a wood block or other hard, flat surface. Wet the thumb and forefinger of the hand opposite your drill hand with oil. Grip the middle of the pin with these fingers and start up the drill. Eyeball a 45 degree angle and press the tip of the spinning firing pin to the paper. Grind a bevel to about 50% of the tip diameter. Now you have a small truncated cone tip. To round it, wrap your 220 grit paper around a rubber sanding block(secured in a vise) and press the spinning tip directly into it. Do this in several spots till the tip is nice and rounded. The soft rubber backing allows the tip to be rounded. Check protrusion and correct by polishing more. Check often so you don't shorten it too much. Finnish by spinning the tip on 400 then 600 grit to polish. You should have a near perfect semi-hemispherical tip. You may want to first practice with a nail to get the feel for it. Link to comment Share on other sites More sharing options...
724wd Posted November 23, 2005 Author Report Share Posted November 23, 2005 sounds like a good plan of action....thanks! Link to comment Share on other sites More sharing options...
z1r Posted November 23, 2005 Report Share Posted November 23, 2005 In case you didn't already know, protrusion should be .055' +/- .005". Link to comment Share on other sites More sharing options...
724wd Posted November 23, 2005 Author Report Share Posted November 23, 2005 i had .055 to .065 as my goal ... but will adjust, thanks! Link to comment Share on other sites More sharing options...
z1r Posted November 23, 2005 Report Share Posted November 23, 2005 My newest toy, a Husky M46 in 9.3x57, has protrusion of .065" plus a slightly large chamber so I'm getting primers backing out of the pocket then slamming into the pin. It pierced one as a result. I'll be fixing that before this weekend. Link to comment Share on other sites More sharing options...
724wd Posted November 23, 2005 Author Report Share Posted November 23, 2005 yeah, pierced primers dont sound good at all! .055 it is! Link to comment Share on other sites More sharing options...
z1r Posted November 23, 2005 Report Share Posted November 23, 2005 yeah, pierced primers dont sound good at all! .055 it is! 7377[/snapback] Especially in a 96. Luckily, the 9.3x57 is loaded to 43,500 psi. Very mild thank goodness. Link to comment Share on other sites More sharing options...
BobVZ Posted November 23, 2005 Report Share Posted November 23, 2005 Z1R, I had a similar chamber problem with a R. FAMAGE .30-06 Columbian Mauser, re-chambered and bored from 7x57. At low pressures the primers were backed out and there was noticable casehead swelling. The fireformed swelled area measured .475. Compounding the problem was the fact that all three brands of brass I was using (Rem, Win and Federal) had .465 caseheads rather than the .470 indicated in the literature. My American made 7x57 and 8x57 brass also have .465 heads. Ten thou is a lot of expansion and FL resizing accelerated casehead seps. I eventually wound up using a LEE handloader to necksize only. I've checked some European made brass and it runs .470. Link to comment Share on other sites More sharing options...
z1r Posted November 24, 2005 Report Share Posted November 24, 2005 Bobvz. that sounds a lot like my problem. Luckily for me the chamber appears oversize at the shoulder area rather than the base. There was no detectable swelling at the base. I was going to try to salvage the brand new expensive Norma brass I got by fire forming to the chamber. the idea was to seat the bullets out til they touched the lands then firefrom with an appropriate load. Well, i can't touch the lands, lol. I guess I'm stuck forming cases from .30-06 brass and adjusting the die so I get a nice little crush fit on the cases. I'm going to check wit Lee on monday to see about a collet die so I can necksize only. Link to comment Share on other sites More sharing options...
BradD Posted November 24, 2005 Report Share Posted November 24, 2005 I know everyone knows that headspace (interior chamber dimensions) causes the primer "creep" protrusion, but fixing it sure is a pain. Some suggestions include short sizing the neck top make a false shoulder thereby holding the case tight enough back against the bolt face until firing, thus sizing the case to the headspace of the particcular chamber. I'm working on some AI's that have this problem and so far the "false shoulder" drill hasn't worked real well. There is less protrusion each time, but the case will be shot by the time I do it enough times to make it satisfactory. I've also heard expand the neck with the next neck size up (ie" .30 to a 8mm) and then resize back again leaving a false shoulder" thus leaving a more positive bearing surface to hold the case back until firing. Can't bring myself to do that. For those who haven't heard how it works: case shorter than chamber; pin hits primer, pushes case forward; cartridge ignites in forward positon heaving space between case head and bolt face; pressure either: 1) pushes primer back leaving it protruding or 2) forces case head stretching and eventually splitting. Or both. On the primer pin protrusion which is really what I wanted to write about, Kunhausen says .055-.065" with .060 being optimal (p. 58). I've been told even .070-.075" doesn't really matter, by reliable people. Here's the kicker, I recently put in a David Tubbs Speedlock firing pin and spring. Great stuff! However, when I checked the firing pin protrusion it was a whopping .125". I almost fainted! One thing about buying Tubbs stuff is that you can always call and yack with David or one of his guys. Really nice, really helpful. So, I called and asked about turning down the unusual steel thats in the tip. The reply was, "why bother?" Stunned, I mumbled something about that's what you're supposed to do. They said they have studied this and it's pretty much a myth. With modern primers and harder, thicker anvils all that is going to happen is that the primer body will crush till it's done and the firing pin will stop. You can't punch through solely with just a long primer nose. They are really smart there, but I wasn't convinced. Too many years doing it the traditional way. However, I decided to try it a bit. The gun is a .338 Win Mag on a recycled Browning FN 98. Put on all the safety gear I could find and closed my eyes and fired. Gun went bang primer looked fine. Have probably fired a 150 rounds that way without the slightest trouble or anything odd about the primers. And believe me, I check every one! I still am not comfortable with this new thought, though, and will eventually turn it down anyway. Just thought I'd share that with you. Should stir up somebody. I'm not recommending anything but the usual way. Brad Link to comment Share on other sites More sharing options...
BobVZ Posted November 24, 2005 Report Share Posted November 24, 2005 z1r, A method outlined by R.A. Boone in the 1994 edition of Handloaders Digest, describes a procedure for fireforming 338-06 Ackley Improved from .30-06. This involved expanding the casenecks one caliber higher (as BradD suggested). Then setting the shoulder back just enough to chamber with the FL die. This eliminated case-stretch and headspace problems according to the author. Headspacing will be at the point of the case-neck and shoulder junction. You could accomplish the same thing by expanding to .375 and pushing the neck back with the 9x57 FL die untill you can just close the bolt. Bob Link to comment Share on other sites More sharing options...
z1r Posted November 24, 2005 Report Share Posted November 24, 2005 Bobvz, I was trying to avoid that route simply because I don't have an expander of the next large caliber. i do have a .416 but I think that will work things a bit too much. I think my approach of simply forming the cases .020" longer results in about the same thing in effect. I get a nice little crush when the case is chambered. We'll know on Saturday. Otherwise, I will be looking/making for a .375 expander. I wouldn't want to use this approach on the .30-06 brass but on the new Norma cases i got this should be a viable approach if needed. thanks for the suggestions. Brad, First I'd make sure that protrusion was measured with all the parts assembled not just by dropping the FP into the bolt. Second, the BS about how wonderful modern reloading components are is wishful thinking. Just last Sunday, after church of course, I blew a primer on my 6mm rem using factory loads. The primer blew at the side of the cup where it is curved. Obviously a defect as the pin strikes no where near it. Just another reason I limit my pre-98s to loads in the under 45,000 cup/psi range. Link to comment Share on other sites More sharing options...
BradD Posted November 24, 2005 Report Share Posted November 24, 2005 Mike, I'm glad you went to church before you tried it. Frankly, I try to stop by at St. Francis for a couple of quick ones before I shoot that long FP. I just thought all of that was interesting. I don't recommend anything but going by the book. Let me know if you come up with a whiz-bang way to stop the case stretching besides the undesireable necking-up, necking-down tap dance. Brad Link to comment Share on other sites More sharing options...
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