Reloading video and brass growth

[Grimstod]

Ok so I did a reloading video and I thought I would share it here. Please feel free to give me some constructive criticism. I know I am not perfect. Wish I was. :
[youtube]http://www.youtube.com/watch?v=5qFHR-JUDNw[/youtube]

Now here is the question and after you see the video you will probably know why I am asking.
I hear conflicting comments on how much to cut your brass after establishing chamber depth. One reloading instructor that I have fallowed for some time now at wildernessmeans.com says you should cut your brass to the chamber depth. Other one says to cut it back about .015ths or so. Lets say we leave the brass to the exact chamber depth. Will it grow and bump up over the chamber shoulder and cause serious pressure. Or does it take a peace of brass that is to long prior to firing to move up over the shoulder and cause pressure levels to spike?

 

[Erik Cortina]

You said brass should headspace the shoulder, but you pointed at the rim.

More brass does not give you better bullet release, more consistent neck tension, nor straighter ammo. The only reason to keep brass length to the maximum is to reduce the chance of carbon ring forming.

You should trim brass .10 shorter than max to allow for case growth.

Wether it takes .001" or .010" of extra brass to cause high pressures doesn't matter, you don't want to find out.

The way I measure chamber depth is same as you, but I grip the gauge with .001" neck tension. All I do is chamber the gauge, extract, and measure. No need for cleaning rod nor making a custom case for it.

 

[Grimstod]

Erik the 7.62x54r head spaces off the rim and I set my chamber up when it was being cut to do just that. It's only got about .001-2th of space on the base of the shell to bolt face. I would like to make it .000j butI unfortunately there is variance in rim thickness. Next up on my list of things to do is make a tool to trim the rim and get perfect head-spacing off the rim every time rather then mess with the shoulder.

For runout I do agree with you that it dosnt get you less runnout and it helps you maintain less runnout. Perhaps I should have said that instead. Only when sizing would runnout be minimized by the Forster sizing die because of the way it opens the mouth with the expander ball positioned high on the recapping rod. Think to of it like a drill bit in the chuck of your drill. If it's deep into the chuck then it's kept truer to the chuck. If you put it to the very end of the chuck then it will wobble more.

I did not even know that carbon rings will form in your chamber if your brass is cut to short. Another friend here alerted me of that via PM. Wish I had know this cause I would have listed it.

 

[Erik Cortina]

My point is long neck or not, if the neck is off, there will be runout.

I know your cartridge headspaces off the rim, but in the video you said something about headspacing off the shoulder but you pointed at the rim.

For minimum runout, I do not use an expander ball.

Video is useful for the beginner reloaded looking to get more advanced, but for the advanced, it's lacking some key points, and the mention of a better carbon ring control, which I believe is the only reason to keep brass fit that tight.

Good job on trying to help out some new reloaded out there. Keep it up, you will learn more in the process if you keep an open mind like you are doing so far.

 

[22BRGUY]

Thanks Grimstod.....Good vid, good info responses, good learning! Keep up the good work and stay safe.

 

[Grimstod]

My point is long neck or not, if the neck is off, there will be runout.

I know your cartridge headspaces off the rim, but in the video you said something about headspacing off the shoulder but you pointed at the rim.

For minimum runout, I do not use an expander ball.

Video is useful for the beginner reloaded looking to get more advanced, but for the advanced, it's lacking some key points, and the mention of a better carbon ring control, which I believe is the only reason to keep brass fit that tight.

Good job on trying to help out some new reloaded out there. Keep it up, you will learn more in the process if you keep an open mind like you are doing so far.

Thank you Eric. I do have a lot to learn I won't be bashful about that. I will keep doing these. There are really no good reloading videos for the Mosin crowd that is why I do them for that cartridge. There are tons of videos on the popular stuff no need for me to add anything there.

 

[Steve Blair]

Even if the original intent was for rim headspacing, why would you not use the shoulder? Granted, it's only ~18° but will still provide much better cartridge centering in the chamber if it is in close proximity. The .30-'06 is 17° but manages to provide adequate headspacing.

 

[Grimstod]

Good question Steve. Anyone think I shouldn't ? If I had my own lathe and unlimited time I would try both and give a range report. : after all the bullet never lies about what technique is best.

 

[BoydAllen]

The premise that keeping the gap between the end of the case neck and the end of the neck part of the chamber to a minimum is an assumption that is not born out on the target. I recommend that you listen to the six segments that Jack Neary has on Youtube. In one of those segments he explains that even though his reamer is for a 1.525 max case length, he trims to 1.490, and based on his experience trims often for best results. Keep in mind that Jack is a truly world class competitor, and member of the Benchrest Hall of Fame. As for your "expert" that advises that you trim to chamber length, not only is he full of it, but he is giving potentially dangerous advice, given that some of the clueless out there are following die manufacturers bad advice to adjust FL dies to touch shell holders. That may result in cases that while of correct length, have their shoulders too far back For their particular rifle(for rimless cases) allowing the end of the neck to be crimped into the bullet as the case is driven forward in the chamber initially, during firing. On the other hand, the video work was quite nice.

 

[BoydAllen]

If the gap (within reason) at the end of the neck doesn't affect short bullets, that have little of their shanks in necks, why would it be different for long bullets, that have lots of shank in necks? I still think that this is a lot of lore with no solid proof. This all assumes that one knows how to keep a barrel, including the chamber, clean. I should mention that for years, I made the same assumption, and that is all that it was.

 

[Grimstod]

"1.525 max case length, he trims to 1.490"

This is a syllogism right?

 

[BoydAllen]

It is simple reporting of what he does. His reamer was specified and ground to accommodate 6 PPC cases up to a length of up to 1.525" and he trims his cases to 1.490" a difference of .035". Didn't you watch the videos? I recommend them. If you don't understand everything that he discusses, those things that you do not, are a good place to start asking questions, and further your education.

 

[mikecr]

Yeah I was just going to point out the same as dmoran.
A 6PPC with a competitive load is going to seal very fast -no matter the trim length.
But a 6PPC at 70-80Kpsi is not a ~243win+ capacity cartridge(where very fast high peaking loads are not viable).
The advantage to tight end clearances has nothing to do with bullet length, but a great deal to do with faster sealing for a slower powder cartridge.

The carbon deposits from back flow.
With a big end clearance you have a lower angle(less resistance) for back flow to move into unsealed neck clearances. With this you have pressure both inside and outside the necks which affects consistent sealing, raising ES, and you see carbon sooting all the way to shoulders..
With relatively small end clearance any flow would be at a very high angle, and so there is less. The neck seals faster, and any small flow stops before depositing carbon at a concerning rate.
While it may not be practical for most folks, I have tested 5thou end clearance with several cartridges, 45deg chamber end, and here I get no more than 1/8" of neck sooting, with seemingly lower than normal ES(~8fps). This running slower powders like 7828, I4350, etc, in 6XC, 26WSSM, 7-08i.

Tight clearances of any sort aren't for everyone. But this is not basis to discount their advantage for some.

 

[BoydAllen]

This is more for the lurkers, and less technical readers, but I assume that when running that close at the end of your necks, that you make sure that your shoulder bump is well under control, to prevent crimping on the bullet, and resultant pressure excursions. Many times a good PPC load will show powder fouling on the outside of the neck in the form of a high amplitude sine wave running around the neck, and covering the middle third, this with necks that are .008 to .0086 in a .262 neck chamber with a loaded round neck clearance of from .001 to .003.

 

[mikecr]

I assume that when running that close at the end of your necks, that you make sure that your shoulder bump is well under control, to prevent crimping on the bullet, and resultant pressure excursions.

That would be YES, and with shoulders at least 30deg.

There are wildcat enthusiasts out there running 40+deg shoulders who would COW FF with necks past chamber end, knowing the necks will snap back 8-10thou with this shoulder improvement, leaving them very near 5thou end clearance. With low body taper and tighter body clearances as well, they don't need to FL size and can maintain any dimension and capacity planned for.

 

[Grimstod]

It is simple reporting of what he does. His reamer was specified and ground to accommodate 6 PPC cases up to a length of up to 1.525" and he trims his cases to 1.490" a difference of .035". Didn't you watch the videos? I recommend them. If you don't understand everything that he discusses, those things that you do not, are a good place to start asking questions, and further your education.

I have watched them before but only to the second video. The audio makes it hard to fallow. I will try to get through them and am watching them now for the second time.

I see he is trimming .035 off. This is expectable cause he is shooting a round that has a lot of stretch as other members have stated. I don't shoot any PPCs yet but I see reports of .020ths of stretch per shot. The video I made is for 7.62x54r a cartridge that prefers very slow powders and heavy projectiles that are at least 175gr or heavier. PPC on the other hand likes fast burring powders (according to our website) and these (according to our website) tend to stretch cases more, I don't know why that is though. With a 7.62x54r first firing sees about .009-12ths of stretch then it slows down dramatically to .0025th per shot till about fifth firing without annealing. My recommendation to trim to .004th is actually almost 2x as conservative as you really need to be for 7.62x54r.

 

[BoydAllen]

He is not trimming .035, that is the clearance after trimming. When you fire form .220 Russian into 6PPC the increase in shoulder angle and decrease in body taper, shortens the case. 1.490 is a length that will clean them all up after fire forming. PPC chambers may be of various lengths at the same headspace.
As long as you know what you have, there isn't a problem. I have seen them from 1.5 to 1.525. 1.515 and 1.525 are probably the most common. The reports that you are getting about PPC stretch indicate that in the future you should ignore those sources. They don't know squat. With a properly fitting FL die cases grow at a very slow rate. The reason for the .035 is how that gap performs on the target, in terms of accuracy and consistency. Even though he has all that room he trims often, because he gets better results by doing so. For the average shooter, with even a pretty good varmint rifle, some of the stuff that Jack gets into is pretty esoteric, but hearing it won't hurt you any, and it is a unique opportunity to learn from someone with the very best credentials. Are you making any attempt to keep track of shoulder bump, and do you know how much your die reduces the diameter of shoulders from as fired or near the head about .3 up? Shoulder bump and die to chamber fit are the biggest determiners of case growth (assuming that it doesn't two men and a boy to pull an expander ball through your necks). You may have a ways to go on getting a handle on what is taking place, but as long as you are having fun, and are safe, you are fine. Tell me about your video equipment and editing software the video work was very good. I have been playing with shooting some. If my results are as good as yours are, I will be very pleased.

 

[Grimstod]

Boyd you have me measuring stuff again ;D Shoulder bump is something I will start paying closer attention to once my Redding busing die gets here.
So I just finished measuring these after reading your post.

Left to right:
3.660 Russian Match grade 200gr Very consistent too, almost down to the .2gr on powder charge.
3.672 First firing so that is about 0.012 of growth there
3.672 PPU factory brand new not fired yet
3.677 PPU shot, resized and reloaded. Oddly it grows here. This is puzzling and I checked a few other loaded ones and they are the same.
3.671 PPU fired a second time after getting the same reloading treatment of the one above (left if you look at the photo).
By the way I set my chamber to give me a 0.001th of crush on closing. Expander doesn't take much effort I use .3095 expander and shoot .311 bullets with this gun.

 

[Grimstod]

Tell me about your video equipment and editing software the video work was very good. I have been playing with shooting some. If my results are as good as yours are, I will be very pleased.

I use a JVC camera. Its really poor quality. I am a Graphic Designer by trade so my standards are high. Next SLR I get will have video and then I can get really clear vide. For editing I use iMovie if I am in a hurry and Final Cut for longer ones or stuff that I want to be more picky about.
If you ever have any questions feel free to PM me. I am always glad to help with stuff like that. Good luck shooting some video. I look forward to seeing it. You must send me slink when it is up.

Here is another video I just did. Wind was terrible so I had to dub out all the sound and replace it later. You may notice my mouth doesn't always move with the voice over.
[youtube]http://www.youtube.com/watch?v=pCMoxLHmePA[/youtube]

 

[Pres100]

I would love to see some Boyd Allen videos