To size or not

[Will]

I once read that for every .001 you size your bullets your group will enlarge by 1MOA. Is there any truth to that?

[44man]

Of course! If you start with a boolit that fits the gun and keep making it smaller, groups will get larger. It is not the sizing itself but you are ruining the fit. Almost every time it is better to shoot as cast unless the boolit is WAY too large to fit the gun. The big problem is that most moulds will not cast large enough to start with and there is no reason to make them smaller.

[felix]

Yes, because it is extremely difficult to keep a longer boolit on axis throughout the sizing process. Best to let the gun size the boolit when/where ever possible, short or long boolit. However, the use of a crimping style gascheck requires some sort of attatching tool. A swage tool would be best, and that kind of tool would require extreme care of boolit material and its size before swaging. Not worth the hassle except for money BR matches. ... felix

[44man]

I seat my checks with a size die either the same size as cast or a shade larger and only run the base into the die far enough to crimp it. I have also run the boolit all the way in to lube but I never actually size the boolit.
I agree with Felix that a long boolit will be ruined by sizing but even a short boolit sized too much will size more on one side then another. There is just too much spring in some sizers and it takes a lot of work to get rid of it. Most push through sizers are better but not as good for seating checks straight.

[Char-Gar]

Taken as a blanket statment I would say the answer is ....it depends. How you size a bullet will make a great difference that how much you size. Sizing with a nose first/push through set up will do very little damage.

You can do allot more sizing nose first, shoave on the base sizing without any ill effects than you can using the old base first, shove on the nose sizing machines.

In a perfect world, a bullet will fit the individual rifle without sizing, but we don't live in a perfect world. In this imperfect world, we often need to size enought for the bullet/round to chamber without damage and let the rifle take it from there.

[Dale53]

I and others on board here have successfully sized bullets considerably more than .001" with success. Most of us would say, however, that less sizing is better. The best of all is a bullet whose "as cast" diameter is perfect. That is how my Schuetzen rifle bullets are handled - AS CAST. However, that would mean a separate CUSTOM bullet mould for each rifle, pistol, and revolver.

Most of us can get by quite nicely with one mould for several different guns if it is chosen wisely for its as cast bullet diameter (slightly larger than the largest required bullet then size for the rest).

However, what has NOT been mentioned here, much, it that the WAY you size can be critical. The Lee "push through" sizing die is a SUPERIOR way to size bullets. The bullet is self alighning and is sized "on axis". You can get away with more size down with this method without damaging the bullet. The Star lube/sizer used with a flat nosed punch and sized nose first works the same way (with the distinct advantage that lubing is done at the same time). Both the RCBS sizer/luber and the Lyman sizer/luber are "inferior" methods of sizing. However, I use the RCBS and have used the Lyman with excellent results. You just have to be more careful, particularly with soft bullets. I use the STAR sizer/luber with my bulk loading of several calibers that I load in volume. Those loads do NOT take a back seat for accuracy, either. Using proper bullet moulds, good lube, the Star sizer/luber, and a Dillon 550B enables me to spend more time shooting than working in the shop and the results are excellent. No more, of course, than most of the others on board here. I have the advantage of being able to prove or disprove my theories with the aid of a Ransom Rest. You can also do good work with a scoped pistol and a good rest. When I was sonsiderably younger and had better eyesight, I could do pretty dern good work off a rest with the issue sights. I can still perform with iron sights but my groups are noticeably better and more consistent with a scope or the Ransom Rest these days.

BPCR bullets present their own problems. They are normally soft (typcially as soft as 30/1 lead/tin) and LONG. Sizing these bullets in a lube/sizer like the RCBS or Lyman CAN cause serious damage. I have some moulds that I shoot "as cast" (pan lube)and some that I pan lube first and then use the Lee "Push Through" dies. Either works at the highest level. Pan lubing as I do it is not particularly slow and tedious. I do several hundred at a time in cake pans and if you carefully monitor the lube temperature, you can just push the perfectly lubed bullets from the lube cake with little trouble or effort.

It's kind of like that old saying, "Horses for courses".

Dale53

[Bass Ackward]

Some peole really get wound up about sizing. And I used to be one.

But I have come to believe that you do what you have to do to get something to chamber. I have attempted to ruin bullets that were crappily molded, outta balance, outta round and drilled holes that were off center and they still shot as good or BETTER. And .... I have had perfectly weighed and measured bullets that didn't.

The only time sizing bothers ya and it don't matter whether a die does it or the rifle, is when you have a void in the bullet base. Then it will size off square under pressure and act like a bad crown and throw a flier.

So I size when I need to and prefer a nose first method since that is how the gun prefers to do it for some reason.

[leftiye]

One thought is that the lead that is moved around by sizing becomes soft lead, as soft as it gets. Swaging or sizing breaks down any crystalline structure in the metal, such as may have been created by water dropping, cooling, or heat treating. It becomes soft lead (like pure lead), and will be more prone to lead your barrel unless treated (reads loaded) accordingly. Not to mention gas cutting due to sizing too small.