This is a pretty broad topic but I assume that most people, including myself have biases we bring into the initial bullet seating depth on all “new” or “new to us” rifle/barrel. What’s your starting point before you start to go further in or further out and how is it impacted by bullet design?
I guess this is more directed to long guns and shooters looking for small groups but any opinion is valuable. Thanks, Bill.
A “Measured Response” is as effective as tongue lashing a stuck door.
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I was enjoying following this topic. I am hoping it will continue again soon.
:-)
JB
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MP 1886
You were using a military surplus powder, virtually all military powder specifications include flash reduction. Since the addition of flash reduction salts costs $$ and reduces powder energy most reloading powders don't include them. No surprise the powder was working as it was designed to.
If you want to read about balancing receiver stresses, get Harold Vaughn's book "Rifle Accuracy Facts" He did it using accelerometers. Yes, it is important the receiver holes are symmetrical.
Steve
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To clarify my earlier post I had error by confusing rockwell number with brinell.
Turns out I'm not perfect either, ha!
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John
The short nose [non-bore rider] ogive of the 30 XCB bullet was tapered to mate with the leade taper of the 30 XCB reamer. That perfect ogive to leade fit has worked very well with not only own HV (2400 - 3000+ fps) shooting but also with several others. However, I've also had excellent results with the 30 XCB in commercial .308 and 30-6 chambers along with military chambers. The taper of the XCB bullet did not match the leade taper in those. Perhaps the gentile engraving which the mated the bullet to the leade has some merit after all?
LMG
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SAAMI experts are writing guidelines for professional ballisticians operating in labs where the use of a universal receiver is the accepted form of test equipment and the bench where the test ammo is loaded is only a short walk from the gun. If you reread the section carefully you will see that the word "twist" isn't used nor inferred. "Rotated" is the operative word used to describe turning the cartridge end for end and then tipping it into the chamber of the universal receiver. At no point do they mention twisting the cartridge between the fingers or tapping it anywhere. They are not setting guidelines for amateur's and hobbyists shooting rifles at their local club. In those cases you are free to do what works for you. Squid Boy
"Squid Pro Quo"
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John
I said it because the fit you two are talking about is the Devil and can lead you down the wrong frustrating road. This doesn't hold true to breach seating. Then is unless you push the bullet into the bore not centered.
Shooting super hard cast and or Linotype or using slow slow powders isn't the Holy Grail either. You shoot high velocity Linotype and you may very well shoot your throat out as if with jacketed.
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Larry,
Your experience pretty well matches mine.
I agree with you that "jam" and "crush" can be misleading. To me, they imply great force and maybe distortion. Other terms or phrases can be more specific.
John
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MP1886 said: "John there are cast bullet designs that you DON'T jam into the rifling or forcing. No ways near that and they are among the best for accuracy. I use a lot of them and they have never let me down."
Mp1886,
I never said otherwise so not sure why the comment. Tell us more. if "among the best for accuracy" why don't they ever show up at matches.
John
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Here's how I see it John. You first learn how to cast and shoot cast and go out to shoot for your first time. You gain some experience. At this time you are in kintergarden. One of the first things you learn is to engrave the bullet into the rifling. Your shooting accuracy improves a lot at that point. As time goes on you realize that is only good for lower velocity. If you change nothing and just try to up the velocity the accuracy isn't so good. Engraving the bullet is just a small part of centering the bullet. You have ensure the back end of the bullet enters the bore straight. This is where things become more difficult. Then you begin to learn engraving the bullet isn't going to get you where you need to be.
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John
Like I said, I've no empirical data to demonstrate that cast bullets that are lightly jammed into the leade are more accurate. Just seems they did in all my years shooting cast bullets. Personally, I think "jam" and 'crush" are probably misnomers in they possibly give the wrong impression. I like the bullets to be lightly engraved by the leade which seems to help center them up co-axel with the bore/throat/chamber axis, especially in looser commercial and milsurp chambers.
The technique I use, regardless of what I or others wish to call it, are demonstratively [look at the target posted] effective. The on-target effectiveness of what we do is what counts.
LMG
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John there are cast bullet designs that you DON'T jam into the rifling or forcing. No ways near that and they are among the best for accuracy. I use a lot of them and they have never let me down.
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Well, what do you know, I have been using an official SAAMI loading procedure without knowing they even had one -- except for this part:
"It should be rotated slowly, end over end, in a vertical plane through 360° pausing momentarily when the powder is at the bullet end and again when the powder is at the primer end."
This seems illogical to me. Why let the powder go to the bullet end when it has giggled all to way to the range with the bullets pointing up? This smells like something made up to impress a novice you are BSing to show how much you know, and how difficult cast bullet shooting is. We already have enough of that horse hockey in CB shooting.
Just my moderate and humble opinion.
John
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I know what the replies will be, but what would prevent one if he's on an informal range, or a range without strict rules or range officers, perhaps his own personal range, that thus person is NOT using a universal receiver rifle, from loading the rifle and gently lowereing it into the shooting position? Or perhaps they could use the Gibson Dacron Method??
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Sorry but I took that "he taught you" as more than just a sharing of terminology. I don't believe that you meant twist in the way that Webster defines one of the possibilities for the word. Perhaps you should call it the Gibson twist or the Gibson / Oehler twist and reduce the possibility for misunderstanding. Squid Boy
"Squid Pro Quo"
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Squid Boy
Perhaps you should re-read my answer to you. I said what I used was a "variation" and the procedure was modified for a standard action firearm. The above from the SAAMI manual is for the use of a Universal receiver. You might pull out your Webster's dictionary, if you have one, where in the definition of "twist" you will find it means "a variant approach or method".
BTW, I did not 'collaborate" on the term with Dr. Oehler. I said I "picked up the terminology" from him, considerably different than "collaborate". The terminology refers to a variation of the specific procedure used when testing is done with a regular firearm from a shooting bench. Universal receivers are not fired from a normal shooting bench and there is no action as such or scope to interfere with loading the cartridge straight into the chamber from the rear of the receiver.
Bottom line, so maybe you can "see it" is the "twist" is a variation of the SAAMI procedure to fit the low load density load and the type of action used. My apologies if I did not make that clear.
LMG
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This is the excerpt from the SAAMI Procedures for Center Fire Rifles Section II
IV.HANDLING OF AMMUNITION
A. Cartridges to be tested should be placed in a vertical position with primer-end down in a recessed holding block.
B. When the appropriate test barrel has been properly serviced and the chronograph reset, a cartridge should be lifted vertically from the block. It should be rotated slowly, end over end, in a vertical plane through 360° pausing momentarily when the powder is at the bullet end and again when the powder is at the primer end.
C. The cartridge is then rotated slowly, a minimum amount to enter the chamber, keeping the primer end in the lowest possible position until inserted gently and carefully into the chamber.
D. The cartridge should be seated in the chamber as far as practicable with the fingers. The bolt or breech mechanism should be closed gently in order not to disturb the position of the powder in the cartridge case. The object of this method of handling cartridges is to position the propellant powder at the primer end of the cartridge case by permitting it to fall gently against the primer while rotating the case.
E. The rate of fire should not be rapid enough to cause excessive heating of the barrel. The time between rounds depends on the equipment, as the barrel may be cooled by a constant stream of air on the outside or by directing air through the bore after each ten rounds.
F. Ammunition conditioning should be between 60° - 80°F (15.6° - 26.7°C). G. A minimum of one and up to three warming shots should be fired before firing each series for record. The velocity and/or pressure of these shots may be recorded, but should not be included in the record of the sample.
I don't see any connection between the procedure you mention as a collaboration between you and Dr. Oehler and the SAAMI procedure outlined above. In the SAAMI procedure the case is turned end over end and then inserted in such a way as to keep the powder at the rear of the case. There is no tapping or twisting as you describe. It seems to me that "SAAMI Twist" is not altogether an appropriate name for your procedure and is misleading to a certain extent. Both procedures do allow for the powder to remain at the base of the case but beyond that they differ significantly.
Squid Boy
"Squid Pro Quo"
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Fed my Springfields with that technique for 25 years, but used the right lug raceway, works well to reduce ES, but don't know if reduced group size.
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The SAAMI Twist is a variation of the test fixture loading procedure. The procedure is described in the manual. Of course using a standard firearm, the load procedure is modified slightly. I picked up the terminology from Dr. Oehler some years back. I use the modified SAAMI method he taught me.
Sitting at the bench with the rifle, action open, on bags I have the ammunition in a loading block or a 50/100 round MTM ammo box with the bullet up sitting on the bench to the right. With the right hand trigger finger and thumb a case is removed from the box keeping the bullet up. It is tapped lightly on the bench then twisted back and forth a couple times with the finger and thumb. That is the SAAMI part and the 'twist". The variation is next as the case is inserted into the action case with the rim/head against the bolt while keeping the bullet up at an angle forward. The amount of clearance in the action opening and scope dictates the angle. The cartridge is gently placed on the follower. The bolt is then slowly closed.
The "SAAMI Twist" simply keeps the powder, especially in low density loads, to the rear of the case.
LMG
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Larry, you mention the "SAAMI Twist Method" of loading a rifle above but I have never heard nor read of this technique in any SAAMI resource I have nor anything on their website. Perhaps it is officially called something else since a search of their site comes up empty. Can you elaborate? Squid Boy
"Squid Pro Quo"
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I guess I am a crusher/jammer as over the years I've come to believe seating the drive band or ogive slightly into the leade (ball seat by some definitions) is more accurate. However, I've no real empirical data proving accuracy is better. As I went to the range yesterday to pressure test some 35 Rem loads in my M91 Mauser I like to take another rifle along to shoot while waiting for the test rifle barrel to cool between tests. Thus, I took the M70 target .308W along with a few of the 30 XCB target loads for it.
The M70 is a stock PF stainless that shot 1/2 moa with 175 MKs over Varget back when I was shooting 600 - 1000 yard belly matches. It has about 2500 such jacketed rounds through it. I only use it for cast bullets these days though occasionally (pre COVD anyway) getting over to Phoenix for a CBA match. I use the weight sorted 30 XCB cast of #2 alloy, WQ'd, Hornady GCs sized at .311 (they drop at .3105) the sized .310 in a honed out Lee sizer. They are loaded to a "crush" fit oal over 16.5 gr of 2400 (no filler) in LC Match cases with the flash holes drilled out and fully match prepped. The cases are fire formed and neck sized in a Redding NS dies with a Lyman 31 M die used to expand the neck to .002 neck tension and flare the case mouth. The velocity runs 1788 fps with the SDs (10 shots) running 5 fps +/- and the ES running under 20 fps.
I use the "SAAMI Twist" method of putting the loaded round into the rifle.
I had not shot the M70 for some time which was previous to my cataract surgery. Thus, I needed to adjust the scope so the vertical crosshair of the Leupold 6.5x20 target scope was vertical and had to refocus the ocular lens. I figured both would slightly affect the zero slightly and it did. I put 4 CBA score bulls up at 100 yards. I the fired 6 shots on the "SS" bull (bottom left) after putting 2 shots into the berm to foul the bore. 1st three shots were low right, so I adjusted up 3 click and the next two shots cut each other slightly high right. I went down one click and left one click and put the 6th shot into the 10 ring. Went back to the test rifle for another test string.
Came back to the M70 and shot the 5 shot group on the upper left target. The nine o'clock 10 is the first shot from the cold bore. I always fire a fouler before shooting a string for score in CBA matches as that first shot is usually slightly out of the group, as we see. Went back to the test rifle letting the M70 "cool".
I then shot the five shot group on the upper right target. the first shot is the low ten, again just slightly out of the group. Back to the test rifle letting the M70 cool again.
Next i shot a 5 shot group on the lower right target. Those five are the five center shots over the ten ring with the first cold bore shot being the low nine. Back to the test rifle giving the M70 a cool down.
When I came back to shoot the last five shots a steady 2-3 MPH wind had started coming from 3-4 o'clock. I did not hold for the wind as i wanted to see how much wind drift there would be. The first cold bore shot is the nine out at nine o'clock with the other four cutting the slanted hole on the edge of the 10 ring at 9 o'clock. My past experience with such a wind is to hold on the 10 ring at 3 o'clock. That would have been perfect this time also.
Average group size for the 4 five shot groups was .823" Was a good day testing the 35 Rem and shooting the M70.
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