Case head squaring

[jb1000br]

BTW--I dont know about your cutter, but mine measures right at .500 diameter, so would let a nice untouched rim around the head of a magnum case (.532-535)

and that 416 Rigby mentioned above-- howinnahell do you cuta .590 head with a .500 cutter?

BTW--the trend in 220 russian cases is a cocavity in the rim--tightens up the primer pockets with firing instead of loosening /ubbthreads/images/graemlins/wink.gif cut off the concavity...guess what.

FWIW,
JB

 

[goodgrouper]

Yes, they all measure .500" so it wouldn't work for standard magnums or oversized magnums unless you had a machinist make a cutter head that was .050" larger, and that is exactly what 7MMRHB and I are looking into right now for the .338 Lapua improved. It shouldn't be hard to do.
As for the concave heads and primer pocket tightness, it might very well be true, but 7MMRHB is running a max load of 36.2 grains of AA2230 and a 55 grain bullet and has loaded his cases dozens of times. His pockets are still tight after having the case heads squared. His load clocks at 3925 fps, so you know there is pressure there!
P.S. I would also like to mention that case head squaring done on a Wilson trimmer is very fast. After I got the hang of it, I did 100 brass in 1 hour and 20 minutes and that was with measuring a few and trimming also. That's what's great about the Wilson, you can square and trim very quickly. All you have to do is flip the case holder around!

 

[jb1000br]

[ QUOTE ]
Yes, they all measure .500" so it wouldn't work for standard magnums or oversized magnums unless you had a machinist make a cutter head that was .050" larger, and that is exactly what 7MMRHB and I are looking into right now for the .338 Lapua improved. It shouldn't be hard to do.
As for the concave heads and primer pocket tightness, it might very well be true, but 7MMRHB is running a max load of 36.2 grains of AA2230 and a 55 grain bullet and has loaded his cases dozens of times. His pockets are still tight after having the case heads squared. His load clocks at 3925 fps, so you know there is pressure there!
P.S. I would also like to mention that case head squaring done on a Wilson trimmer is very fast. After I got the hang of it, I did 100 brass in 1 hour and 20 minutes and that was with measuring a few and trimming also. That's what's great about the Wilson, you can square and trim very quickly. All you have to do is flip the case holder around!

[/ QUOTE ]

So do you square the case head to a random point, then turn it around and trim it to the SET depth?

If the trimmer is SET, and you cut to the SET, you cant turn the case around and keep trimming...it is already to the SET length. Im confuzzled.

JB /ubbthreads/images/graemlins/confused.gif

 

[goodgrouper]

You set the trim length first, but don't start trimming. Case head cutting is done first until you feel the cutter making 100% contact and there is no rubbing or resistance feeling in the handle. The feeling is kinda hard to explain, it is one of those things you just develop a feel for. My first 100 took about 2 1/2 hours, then my second 100 took about 1 hour and 15 minutes because I started to feel when it was done. For this squaring step, you don't actually rest the case holder against the stop. Leave about 1/16 of an inch clearance and just put resistance to the cutter by pushing on the back of the case holder with your thumb. You then just flip the case holder around and push lightly on the back of the case holder against the stop until the cutter stops cutting like normal. Waallahh! Your case is trimmed and squared in about 30 seconds.

I can hear some of you already saying that would not be consistent, just pushing on the case with the thumb and not having it against the stop. But in fact, it is very consistent once you get the feel of the cutter and how much it is taking off. For the first little while, you will have to take the case holder out of the trimmer body and see how much of the case has been cut until you get the pressure down right. You know you have gone too far if it makes a cut all the way across the head, or if the stamped lettering starts to disappear. What you want is for most of the head to get cut, but there should still be a little banana shaped uncut ring around the outside edge on one side. This is the low spot, and you have now cut everything down to be level with that side.
Sometimes you'll get a domed shaped case, and it will show the uncut part all the way around the outside edge. This is as it should be because you have just removed the top of the dome, and all that is left is the flat surface cut down to be level.
On the flipside of that, a dished shaped head will start to cut the outside edge first leaving an uncut center. You can imagine the angle of the cut part and the uncut part. It is like 1 millionth of a degree! A lot of times, when I was getting the hang of it, I would have not cut more than a quarter of the case head and would stick it back in the cutter and lightly just push harder and the cut would go almost all the way across the head! That is how shallow the angle is that you are cutting! That's why I say that this process can be done anytime in the case's life because your just not removing very much material. If the brass wall ahead of the web can not stand a .001" increase in head space, then you ought not to be shooting that thin walled brass! Just resizing brass that thin would result in case head seperation in your die!
The truth is that a .0005 to .001 " increase in headspace won't hurt anything. The brass will flow forward .001" one time and then be done. You won't even be able to see a difference in the brass walls. You might just see an improvement in your groups!
Anyway, I hope this helped. --goodgrouper /ubbthreads/images/graemlins/grin.gif
P.S. I have pictures of some case heads if anyone is interested in posting them for me.

 

[7mmRHB]

Since there seems to be numerous skeptics on this subject, I thought I would try to make a case for making case heads square. I've been doing this process as goodgrouper has described it for 8 years, and thousands of brass, including standard magnums. There are other reasons to include this step in your brass prep regimen besides better case head to bolt face contact. Unsquared cases effect the tolerances of your sizing and seating dies. With the high point having a high percentage chance of being inside or outside the shell holder from case to case. Even an Arbor press is effected because in any given lot there are concave, convex, besides high on one side brass, along with an occosional square one. I believe this can be one cause of inconsistant "feel" while chambering your reloads. A smooth square case head snugged up to a trued bolt face can handle more pressure, and greatly reduce the amount of brass flowing into ejector holes or extractor notches, while giving you a much smoother bolt lift and less brass build up on the bolt face while fireing those warm (or hot) loads. A factory or unblueprinted gun is going to have the bolt high side and the case high side come together more often than you would like, causing even bigger gaps between the two again causing tight or inconsistent chambering. The thought of firing my gun with only a few thousanths of an inch of brass making contact with the bolt face is revolting at best. Brass will not square itself during fireing and even after multiple hot firings, the case heads remain as before, Convex, concave, or highside take goodgroupers word on this since I proved it to him with his own guns and brass fired 9 or 10 times. (Lapua 6.5-284).
Goodgroupers description of the process was a good one and a first timers learning curve is quick. My process time for this step is 100 per hour which includes trimming to length. Standard magnums leave a tiny burr sticking up about 2/3 way around which I deburr with a fine file. This adds more time but not alot, and knowing that each brass is at its best can only build your confidence. Every make of brass is out of square. Dealing with it is not that tough. Wilsons disclaimer is because of the liabilities concerning the promotion of their product as the cure. Use your head, common sense says that if the case head stamp numbers are disappearing before you get half way across, find some better brass.
Good Shooting,
7mmRHB

 

[goodgrouper]

I am sure glad to see you on here 7mmRHB! Welcome to the forum, and thanks for backing me up! I was starting to feel like I was all alone against the world.
Your extensive knowledge will benefit those who use this forum who maintain an open mind! Welcome. /ubbthreads/images/graemlins/grin.gif

 

[RBrowning]

I see where perpendicularity (I don't think "squareness" is a word) can be an advantage. I don't see any downside to doing it other than a small investment in time when you first get the brass. But I would like to know how much of an effect this has on sorting by weight. The premise of sorting by weight is to get a more consistant volume inside of the case. Now you may have two cases that have identical volumes but one is square and one is not. In removing metal to make it square you have now changed it's weight. The same could be asked of primer pocket uniforming and flash hole deburring. Each is taking out a very small amount of metal, but could they add up to enough so that you would put cases with equal volumes into two different classes because you "remachined" them? Also has anyone actually measured how much out of square/flat we are talking about? And does it remain constant after firing?

Just curious.

 

[goodgrouper]

Rbrowning,
You pose some excellent questions! After doing all the match prepping you talked about, including case "perpendicularity" (I love that word, it makes us sound so smart!) the brass weight spread went from 1.2 grains to 1.6 grains high to low. So it did make some difference for sure, but it still was pretty insignificant. I could still tell that it was great brass. Now, I will tell you upfront that I have only done this trick to Lapua BR brass, so I don't know about the other kinds of brass. 7MMRHB could tell you way more about it than me. I can tell you that it would be a possibility to weigh the brass before and after you cut it. Then you would know if it is a variance in volume or just machining shavings. On that one case out of 200 that was .006" short in the neck, it also weighed less but I knew why because I measured it and just kept track of it by putting a notch in the head.
As for your last two questions, the degree of how much square/flat there is seems to be more than I thought it would be. Up until this experiment, I kinda thought that it would be pretty insignificant, but as I finished up the 200 rounds of excellent brass, I looked down at the pile of shavings that came off those heads and now I would have a hard time NOT doing this given my perfectionist mentality.
And yes, it seems that once it is fired many times in a blueprinted action, it remains very constant. In other words, it is a one time deal like flash hole deburring.
good shooting! -goodgrouper

 

[jb1000br]

Not sure if i missed this or not, but have you seen any QUANTITATIVE advantages to this process. before and after etc...?

thanks,
JB

 

[goodgrouper]

Well, the first thing that happened after doing this process was a big jump in confidence knowing I had done everything I could to make my ammo as good as it could possibly be. As far as a noticeable difference in accuracy, all I can say is that my 6.5-.284 with it's square contact to the bolt face has shot a 28" X 14.5" group at 1 mile in decent mirage. As far as testing accuracy before and after the process, I am currently in the process of this test with a friends 6mm dasher. I will post the results as soon as I get them. /ubbthreads/images/graemlins/grin.gif
7MMRHB, have you tested before and after accuracy on anything you've done?? If so, you could answer jb1000br's question better than I. /ubbthreads/images/graemlins/wink.gif

 

[daveosok]

Has anyone thought of this?

When you lock your bolt down the sear has a small spring underneath forcing the sear upwards to catch the firing pin. This force even if it is ever so slight in a stock Remington rifle will push the bolt upwards and because of the slop in the action cause the bolt to seat at an angular plane off from the centerline of the action. This will cause the bolt face to be out. If your squaring case heads and your bolt is out of square (by no means through blueprinting) wouldnt this negate the purpose of squaring case heads?
What I did on one remington was to tig weld a small bead completely around the bolt at the rear where it would have the greatest contact area in the action and cylindrically ground this weld bead down to fit in the action to take up the slop. The front doesnt receive this weld bead as the counterbore in the barrel aligns the bolt. I slightly taper the front of the bolt boss about 1.5 degrees and the counterbore in the barrel is slightly tapered to a 1.5 degrees this algins the bolt to the barrel.
I saw no great improvement by doing this although I now know that the bolt is centered to the bore of the barrel. Much more work was done to the action like cylindrically grinding the outside so that the bolt race way/ bore was concentric to the od.
The violent action accompanined with the firing of any weapon the stresses involved play havoc on the material strength and consequently bend and twist the metal so you will still be out of square at the exact moment of firing.
I will give this a shot in the above mentioned action and see if there is any difference.
This idea requires testing because I do suspect it holds some sort of advantage as it is no doubt another step to reloading which is already time consuming.
For the fellas that shoot 1000 yard comps do they square there case heads?
Its really ironic though when you think about it everything we go through to eek out the very last bit of accuracy only to see guys show up with a bone stock factory rifles with Black Hills ammo shooting groups suggesting they do everything we do but you know they dont and Ive seen this a time or two. Says something for an "exercise in futility" doesnt it /ubbthreads/images/graemlins/grin.gif makes you wonder if what your doing actually makes any sense. Course it does as the industry for handloading wouldnt make any money nor would gunsmiths with prominant names be talked about.