General case length and trimming questions

RC20

I agree that there comes a point where we start to over think such things and any differences get lost in the noise of environment factors and shooter error.

Oh and Guffy I don't use the split case myself any more. I prefer sizing only the first few thousandths of the neck with a bushing die or doing a very light neck sizing using a collet die

Too tight a neck will give errors because the lands will dig into the bullet jacket or even into the core throwing the reading completely off. After chambering if there is any sort of groove in the bullet where it contacted, toss it and start over

I don't do this but if you want to get real anal pull the extractor before chambering
 
While all that is true might point was , just when I thought I knew exactly where my bullet was in relation to the lands . It turns out I didn’t.

As for will it matter , I think we all have seen just about any one thing does not seem to be all that noticeable.
 
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I always freak people out when I say I don't care about whether my reloading scale is accurate as long as it is precise. The key is in recognizing what worked then duplicating the measurements and weights then repeating it as precisely as possible.
 
The thought that I have always gone with is making good hand loads involves eliminating variables. Thus building consistency.

We all have our perks and peeves, so we decide that one variable is not detrimental to my cause and others are.

I have been rolling my own for so long that I have determined what makes a difference to me and what does not.

This does not mean that I didn't use to be anal about everything, because I did, to the point that it became laborious at one point.

So, I stepped back, re-evaluated, and picked apart my procedures. Now I am a happy hobbyist that enjoys a lot more than I once did.

As always: whatever floats your boat. If it works for me, then screw what everyone else is saying.
 
When ever your headspace is less then zero , let's say you sizing with a .002 space from base to shoulder datum and you know your base to ogive , and your seating that bullet to a zero jump , with that .002 headspace sized case , once that firing pin drives the case to the chamber shoulder it jams the bullet to a .002 jam . I set my cases to .0015 - .002 and my seated bullet to a .002 jump.
 
I don't do this but if you want to get real anal pull the extractor before chambering
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Guilty. I hated the yank and some evidence it can distort, so I size sans and use an M die to set the neck opening.

Minimum sizing as evidenced by a 2 to 4 thousandth shoulder setback. I use Lee rings on the dies so I can touch it back and forth a bit to fine tune. Works good.

As for bullet seating, I start 10 thousand off the lands and see what looks best then run it on out from there. I havn't found one that wants to be any closer (or is more accurate closer)
 
I do the Berger test with minimum load before doing the powder workup these days. Find the a good rough depth then find the powder load. I seem to get dialed in faster using that method
 
As for bullet seating, I start 10 thousand off the lands and see what looks best then run it on out from there
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How do you do that? I want to know the length of the chamber from the beginning of the rifling at the end of the throat to the bolt face. I must be the only reloader that does it 'complicated' way. Proof? Too many excuses by reloaders to do it 'the easier way':confused::eek::D.

F. Guffey

Remove the extractor? I can only guess that is a rule because a bench rester said, "DO IT".
 
I must be the only reloader that does it 'complicated' way. Proof? Too many excuses by reloaders to do it 'the easier way'.
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As long as it works for us does it matter? When installing barrels I use quality GO/NO GO gages to ensure the headspace is set accurately. Accuracy is necessary to do the job correctly. When reloading the goal is precision not accuracy. If all 50 rounds in that box are all as close to being identical as I can make them I am happy

If you don't understand the difference between accuracy and precision, I suggest you educate yourself.
 
As long as it works for us does it matter? When installing barrels I use quality GO/NO GO gages to ensure the headspace is set accurately. Accuracy is necessary to do the job correctly. When reloading the goal is precision not accuracy. If all 50 rounds in that box are all as close to being identical as I can make them I am happy

If you don't understand the difference between accuracy and precision, I suggest you educate yourself.
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The question was about determining the length of the chamber from the rifling at the end of the throat to the bolt face. I understand you can not help yourself but it appears you almost talked it to death.

I was wondering if RC20 could determine the distance from the rifling to the bolt face, do not get me wrong, I was impressed with that tid-bit about removing the extractor, there are rationales and reasons for removing the extractor I do not believe the reason "cause" is good enough. I go not believe, "because I have a bench rester friend and he told me to do it is a good reason.

F. Guffey
 
fpaxM7.jpg


I have this target showing that .010 increments in seating depth matter in accuracy .

This target/load was done using the OCW method and this was my final seating depth fine tuning of that load and process .

The final result was this load . That's a 1" orange sticker in the center and was shot at 300yds

JXcHP9.jpg


So at least for me and this load .010 difference in seating depth shows on paper . The question would seem to be does .005 ? If so getting the distance from datum to bullet ogive consistent would seem to be pretty important ???
 
The question would seem to be does .005 ? If so getting the distance from datum to bullet ogive consistent would seem to be pretty important ???
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According to the big boys in LR benchrest .003 matters. I figure for someone like me that difference would get lost in the noise so when I get to .5 MOA I call it good enough.

Good shooting BTW, I'd take that last load to a 300 yard match with a smile on my face and a song in my heart.
 
For all those discussing measuring to ogive, datum point, shoulder set back, distance to the lands from some magical mystery point and how to measure it, I have a couple questions, #1, how does that answer this...?

I'm still new to reloading and looking to refine my case trimming technique. I'm reloading 30-06 for my M1 Garand and was hoping someone could help with answering some general questions.

1) Can I prolong the life of the case by trimming less, and trim to the MAX case length of 2.494" rather than the Trim-To Length of 2.484"?

2) Can I get more accuracy by trimming to the MAX case length of 2.494" so the ogive of the bullet sits 0.010 further into the free bore?

3) I use a Tri Way trimmer to trim my brass and the case length varies with each case a little to a lot depending on the starting length of a given case. To what decimal place do I need to match my cases in case length to produce the best groups?
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The OP asks about case trimming, NOT how to measure distance from ogive to lands, or so it seems to me.

Next question, can you tell us if ammo loaded to ".xxx" off the lands, (set that way with whatever system you use to measure) can you tell us that ammo WILL work in the OP's M1 Garand?? Can you tell us that it will give improved accuracy? Will you claim it will make a difference in an M1 Garand??
 
The OP asks about case trimming, NOT how to measure distance from ogive to lands,
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With all do respect ( and I mean that ) It's called the natural progression of a conversation . The OP mentioned his trimmer indexes off the shoulder and that brought up a few more interesting points that go directly to using that type of trimmer . I might be wrong because I don't remember in detail everything the OP has said in this thread but I think he talked about seating depth as well , maybe not ?


If the OP is satisfied with the narrowed scope of his question I'm more then happy to stop . He may not know this but there are some very experienced reloaders talking about things that at some point he will have questions about . We may be overloading him because he's new to this and that was/is never my intention .
 
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Yes, it did seem to wander into this progression, but at this point it has probably run its course.

To review the answers to Riley's original questions:

Case life cannot be improved by improving trimming precision. Learning to resize to make the head-to-shoulder measurement only about 0.002" shorter than the brass is after firing in your chamber should enable it to feed the Garand and that practice will extend case life if your gun's chamber isn't at dead minimum, in which case, that would be about what you are getting out of the sizing die now.

Accuracy is not affected by trim length within the normal SAAMI case length range, which is 2.474" to 2.494" for 30-06. Don't exceed the high end, but going a little below the low end won't normally hurt anything as long as bullets are seated with adequate depth and you are not crimping.

Case length variation when trimming with the Tri-Way is due to variation in the head-to-shoulder datum measurement after the brass has been resized. That variation will be reflected as variation in bullet jump, but using standard COL's as given by the bullet makers, it should not be so snug that this error source matters a lot in the Garand.

I have owned and rebuilt and loaded for several Garands and can say the most important things about loading for them are to be sure the primers are seat hard and at least 0.003" below flush with the case head. I think the CCI #34 primers are a worthwhile added safety precaution in this application. Use powders that are not too fast for the gun or get an adjustable gas cylinder plug. The old rule of thumb is that any powder that has a maximum charge weight listing of over 53 grains for a 150-grain bullet is too slow for the Garand and will raise muzzle pressure to a point that it can hurt the operating rod. Avoid trying to exceed government ammunition velocities with it. The 150, for example, should not exceed 2740 fps at 26 yards (about 2800 fps at the muzzle). If you are driving it faster, you are probably overworking the op rod.
 
. The OP mentioned his trimmer indexes off the shoulder
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There are a lot of reloaders that can not keep up. I am not one of 'one those' reloaders. I am one of the third kind of reloader. I am the fan of the L.E. Wilson case gage reloaders. I understand you guys:) have a dislike for the datum that is not my problem. From 1938 the Wilson case gage has been a datum based tool. The Wilson case gage measures in two directions, it measures from the datum back to the end of the case head and it measures from the datum forward to the opening of the neck. The length of the Wilson case gage from the top to the bottom is the same length as the case length according to reloading manuals.

A reloader should be able to determine how much the case should be trimmed. A reloader should be able to determine the length of the chamber from the shoulder to the case head. The part that is too complicated for reloaders is the mindless trimming of cases that is not necessary because they do not understand the datum based tool was designed for the reloader to read the instructions.

The instructions suggest the reloader use a straight edge, for me? Not a problem. I use the straight edge and I added the feeler gage and I made a tool with a dial indicator to determine case protrusion in thousandths. Most reloaders use their thumb nail.

SO? The Wilson case gage was designed to be used with trimmers that set up on the shoulder, Do reloaders just go through the motions of reloading to without understanding what they are going?

I know, this stuff I do is over your head; I have one chamber that is .016" longer from the shoulder of the chamber to the bolt face than a minimum length/full length case. When I trim cases for that chamber I add the .016" to the length of the case . If I am trimming cases with a trimmer that sets on the shoulder of the case I do not have to worry about it. 'WHY! ?'

F. Guffey
 
Yep, way over my head. So far over my head I am at the bottom of the Marianna's trench in comparison. I just am not sure how I will struggle on with life.

Shock, I still manage to shoot 1/2 inch groups and have not gone to heck for my being over my head.

So yes, I will bumble along in my plebeian way and I know its shocking, but enjoying myself as I do so.
 
Laughing at or with?

I understand all of that, the one thing I see no humor in is the 'laughing at' I had rather laugh with.

F. Guffey
 
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