Carbine Credits and C.O.A.L. Pollution

For someone who reloads metalic cartridges, I’ve done it very little.  Still, I’ve had problems, with several calibers, in seating bullets.  The seating plug that comes with the die set (you only get one plug) doesn’t fit every bullet shape ever made, which means it doesn’t fit the bullet you’re actually using, even if the dies and the bullet were made by the same company.  As a partner to this phenomenon, the loading manual (also written by the bullet company whose sister company made the loading dies) says very little about seating plugs, or the fact that a plug made for one bullet shape might be a real problem when seating a bullet of some other shape.

With some bullet/seating plug combinations, I find it impossible to maintain a cartridge OAL to within 15 or even 20 thousandths, yet the construction of the press should be capable of easily maintaining a seating depth to within a thou or two.

Another part of this cascade of problems is that depending on the bullet type, the bullet itself may be part of the problem.  Softpoints can be distorted in packaging and shipping, can mash during seating if the plug touches soft lead, or a jacketed hollowpoint match bullet’s meplat can be inconsistent to several thousandths.  The latter inconsistency isn’t all that much of a problem if the seater plug fits OK.  The bullet’s ogive is still being seated to the same position and the base is still seating to a consistent depth inside the case because the seater plug doesn’t touch the meplat (assuming it fits OK) and you can always trim the meplats.

Today I got the primers I ordered last April or May, so I decided to load some of the 110 gr “Varminter” HPs I’d gotten to try out in .30 Carbine.  Brand new cases, all prepped and flared the same, and I can barely hold C.O.A.L. to within 15 thousandths.  The seater plug was made for the round nose 30 Carb FMJ, and the HP’s round nose, made by the same company, has a distinctly different shape from the FMJ, which makes the seater plug impinge on the soft lead corners at the very tip of the bullets.  These HPs, by design, are very soft at the tip.  Some of the bullets get swaged inward at the tip, narrowing the hollow tip opening, raising a burr at the tip and lengthening the bullet.  Others don’t distort much at all.  The phenomenon is binary– either I get a distorted nose and the OAL is 10 to 13 thou over, or the nose stays intact and the OAL is within a couple thou of nominal.  Nothing in between.

Long story short; Die makers should be discussing seater plug issues a lot more, and they should offer a plug for just about every bullet shape, especially plugs that don’t impinge on the soft lead of hollowpoints and softpoints unless the plug is going to match the bullet shape perfectly.  Another plug/bullet mismatch I’ve had results in the mouth of the plug cutting a circle around the bullet like a sharpened punch– the extremely small contact surface area isn’t conducive to repeat accuracy.  As it is, I can always make my own seater plugs, but what a pain just so I can try out some different bullets as a lark.  On a positive note; standard reloading dies are priced unbelieveably low.  You may connect the dots.

We had a rep from Speer in at UltiMAK several weeks ago, setting up some M1 Carbines with our forward optic mounts and high-end combat optics for a LE demonstration of their new .308 110 gr Gold Dot loads (offered to LE only last time I checked).  I’ve thought for a long time that the M1 Carbine would make a good patrol carbine or “truck gun” if one were to use good HP loads in it.  Haven’t heard back from the rep about how the demo went, and I’d sure like to try some of those new Gold Dots.  I guess when they release them to the public they’ll be backordered eight months within a week.  I’ll take a thousand, please.


8 thoughts on “Carbine Credits and C.O.A.L. Pollution

  1. I agree about the M1 carbine making a great truck gun. I used to see them all the time used for that when I was a kid. Not so much any more. ‘course when I was a kid there were millions of surplus rifles left over from WWII and Korea on the market…but I digress.

    They are basically a pistol caliber carbine similar to something in .357 magnum, very light, point well, reliable, easy to maintain, decent sights…all around just a good little rifle.

    Query: In all my reading about reloading (I’ve been reading about it alot because I’ve been wanting to get a press and start reloading myself), I haven’t run across this complaint before. is it because you’re using “unusual” bullet shapes, because you’re reloading to tighter specs than others or is it just something that other people don’t worry about?

  2. To some degree die makers do offer a variety of seating plugs – FREX RCBS for Speer bullets and to some extent – many rifle bullets a seating plug can be fitted either by lapping – spin with valve grinding compound or other abrasive – or glass bedding – spray with a parting compound and glass bed for a permanetn custom seating plug or for one time use form with clay or what have you. And of course defining length with a datum line using appropriate tools rather than true OAL to the bullet tip works just fine as does using a Meplat uniformer (e.g. Tubb) to uniform the bullets.

  3. Sailor; I wish I could answer that. Granted it’s not the most current manual, but combing through Speer manual number 12, I can find no reference to seating plug-to-bullet fit or to possible deformation of a bullet due to a misfit seater plug, or to possible AOL variations resulting from a poor plug fit. They do mention the critical importance of the right seating depth however, and they post COALs for each individual load– to the thousandth of an inch. Their M1 Carbine section lists three different COALs (for three different bullets, including the one I’m loading). Interesting, huh? Also looking through Sierra’s manual, Edition V, I find no reference to this seater plug issue. Interestingly, as I’ve delved somewhat into black powder shooting, I find that one maker of muzzleloading bullets sells a ram rod tip to precisely fit their lead hollowpoint bullets– Hornady I believe it is. The ramrod tip design, which is analogous to the modern loading die’s seating plug, fits both the outer profile of the bullet and the inside of the hollowpoint cavity so as to avoid any deformation of the lead upon loading. So far I know of not one modern reloading die company that has thought things through to this extent. I was hoping someone could set me straight.

    For the time being I’ll assume it’s up to the individual reloaders to make their own plugs when appropriate. This requires a metal lathe and the knowhow to use it well, including using a lathe to cut threads. So far I’ve loaded for exactly three calibers (280 Remington using VLD bullets, .30-30 Win using a variety of bulets [most bullets are fine in the .30-30, with the little HPs being the main issue there], and .30 Carbine using the Speer Varminter HP). All three would benefit from a better seating plug-to-bullet fit.

  4. I have somewhat limited experience with this, but it seems to be exaggerated by the newer, longer bullets such as Berger VLD’s.

    I thought I was going nuts, trying to get some consistency, until a much more experienced friend pointed out that I was actually doing a good job and that it was the ogive length that was the culprit, as even the best of the longer bullets have some variation in length. He pointed out that it wasn’t truly max COAL that was so important, but a consistent length to the spot where the ogive begins and the bearing surface ends, since that is what is most important in relationship to shot to shot consistency. Thus consistent COAL is much harder to achieve with secant ogive bullets than tangent ogive bullets, at least with the common dies available.

    I keep hoping some of the die manufactures will make custom dies available based on the bullet!


  5. Chuck and Bill; you can tell us that stuff, and thank you, but the loading manuals can’t. Does anyone else find that more than a little odd? Yo! Sierra. Yo! Speer. Whaddup? (OK, maybe I’d best check my later, number 13 manual before I start in with the flaming)

    I’ve heard of using an epoxy, or bedding compound, to form-fit a seating plug, but I’ve been worried about the goo sticking inside the die. I assume you have to do it inside the die to keep everything aligned, but then again maybe it could be done using a lathe to align the parts.

    In the 280 Rem using VLDs, another problem in addition to the plug wanting to cut a ring around the bullet ogive, was that COAL was determined by the magazine. We’d have used a much longer COAL determined by the freebore, but we wanted to be able to feed from the mag and the mag was having no part of it. We had to use a slightly shorter COAL (shorter than the already short one) to allow for the variation so the longest rounds would still fit in the mag. Yes; meplat trimming would be the answer there, and/or single feeding rounds into the chamber.

    I got 60 HP rounds loaded for M1 Carbine. I’m not happy with them, but it’ll at least give us some indication of how our two Carbines function with these bullets, and I want to do some terminal effects comparison tests with ball and the HP. I’ll post about it sometime if there’s anything noteworthy.

  6. Might try these or one of the many other RCBS bullet specific seating plugs – there is no Utopia and perhaps a custom fit is necessary but FREX:
    These through the top seater plugs (1/2″ – 20 thread) are available separately and manufactured to fit specific bullets as listed. They are not furnished with die sets or seater dies.
    RCBS Alternate Seater Plug .32 Caliber 62 Gr. Gold Dot Hollow Point
    •Replacement Seater Plug Designed to Match the Shape of a Specific Bullet
    •Through-the-Top Style
    •1/2″-20 threads
    •Not Furnished with Die Sets or Seater Dies
    •Seater Plugs with 1/4″-28 threads are for use with older RCBS dies and can be made on a special order basis. Contact RCBS for information

    RCBS has about 16 Gold Dot specific seating plugs all in stock at Midway USA frex. In times past makers have gone out of their way to furnish seating plugs for specific bullets in response to complaints – this is likely becoming a thing of the past but the makers do try and do respond.

  7. “I’ve heard of using an epoxy, or bedding compound, to form-fit a seating plug, but I’ve been worried about the goo sticking inside the die. I assume you have to do it inside the die to keep everything aligned”

    Again using a parting compound, either as part of a glass beddding kit or using a filled epoxy from the hardware store and Pam or other no stick spray will usually work. A toaster oven or heat gun on low will often setup the epoxy better than waiting and allow an easy burn off and start over. If at first you don’t succeed heat the epoxy enough to break it down and pick it out and start over. Everything is threaded so breaking the seating plug loose by turning it one way or the other after heating to break the epoxy will likely work. There is a squish factor when the seating plug with fluid epoxy hits the bullet and like lube dents in case necks I suppose to much Pam would distort but it’s always worked for me. I’ve had fair results with candle wax for a one shot. In other cases I’ve bought multiple brands of die for the same cartridge to match bullet and seating plug.

  8. I don’t know if they still do it, but RCBS used to make custom seating rods on an individual basis. I’ve sent them 5 bullets and whatever the fee was and in a relatively short while ..vilola!

    It’s worth giving them a call.

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