Guys I need your help. Having a little trouble with the old brain and I cant remember how to set my barrel for .002 set back.
Yes I have 6mm-BR Go and No-Go gauges and I know how to use them. Such as on the No-Go I should see the bolt fall to about the 2-3 o'clock position to save on brass.
What I am getting confused on should I set the barrel using the Go gauge with one or two pieces of tape for a .002 set back? Or do I put the tape on the No-Gauge for a .002 set back? [Darn anesthesia anyway! I feel like Joe Biden some days!]
Thank you all!
Larry
You don't use any tape for setting the headspace. Use the go gauge....insert the gauge and close the bolt and then screw the barrel up to the gauge till it stops. Not tight, just till it stops. Tighten the nut. The nut will tension the threads and create another .0015- .002" clearance. There's your .002" set back. If you want assurance, check it with a piece of plasti-gage, it will tell you exactly how much clearance you have.
"As long as there's lead in the air....there's still hope.."
That tape is hard to measure but i would bet on it being between .003" and .004" thick maybe more depending on the manufacture.
The Dunning-Kruger effect is alive and well.
Tape is not consistent either. Use the Go/No-go. That's what they are designed for. People use tape with a Go gauge so they only have to buy one gauge (or they use tape with an empty case and don't use gauges at all).
After firing it won't matter anyway. Once fireformed set your sizing die for the setback you want. Just don't use that brass in any other rifle.
Flash back thank you Fred. I had completely forgotten about what you said. Good advise on using plasti-gage. Just to be safe, I think for awhile Ill back off on any further action on the fine tuning until this brain starts working again.Originally Posted by sharpshooter
Charlie to your point about using tape instead of a No-Go gauge...heres a video of a guy that does that. https://www.youtube.com/watch?v=l0OxGkncWlQ
Last edited by LDSILLS; 06-29-2024 at 10:25 AM. Reason: clarification
I understand a lot of people use tape. If you want it to be accurate to the cartridge spec then the gauges are the right way to go.
As mentioned, if you only care about fitting the cases to your rifle it doesn't matter much what you use. More headspace means more case volume and the brass is stretched a bit. After fire forming then it is the sizing die setting that determines everything else.
For my initial setting on the 6BR I used gauges. For my .308 I used a fired case for a go gauge and tape on the base for no-go. Both methods work.
I cut pieces of aluminum can rather than using something that can be destroyed like tape. Using scissors I cut out the shape to fit down in the bolt head. I don't remove the ejector so I cut around that. Like charlie said. You set your sizing die to size your brass correctly. It has worked for dozens of barrels.
The Dunning-Kruger effect is alive and well.
Lets clarify folks. I have no ejector and the ejector hole was closed when Fred trued my bolt head.
I did this for two reasons onethis rifle is a true single shot who needs an ejector.
Two, if 6mmBR components remain as scarce as they are I can easily change things back to .22-250, 6mmPPC, or even a 6mm-Dasher.
Truthfully, I have always thought the .22-250 would be a great short range bench caliber, pushing a 53 grain Sierra Match at 3800 to 4000 fps. Sure I'd have to watch the barrel throat, but man can that little pill drill the holes at 100yds and at that speed it cuts moderate wind like its butter. Nice thing also with a .22-250 my as built rig, recoil will be near zero another plus for free recoil bench shooting.
I know this as when it was factory I could shoot a yote and never feel anything other than sore muscles from dragging around a 10 pound gun!
I don't have an ejector on any of my bolt guns either.
Keep in mind I don't hunt.
Recoil is why I went to the 6BR. I wanted 1000yd performance that my .308 had with 175SMK's, but, I hated the recoil. I got what I wanted. Little recoil (yes, I shoot free :) ) and accurate at 1000. It is really superb at 600yd. Soda cans make good targets at that range.
My .223 was ok at 600 but was not good at 1000 (2MOA kind of thing). Which was why I went up in caliber.
If I were shooting at 300 or less I'd still be using my .223.
A little off topic but how would this be for bench. For example its just not a .223 bench day because of 15mph winds. And you don't have a second calibered rifle. So you simply swap to a barrel with a different caliber and a heavier bullet.
Bottomline, heres an invention for someone. Create a Savage barrel Locking ring that doesn't need locked down with a wrench. All you do is screw the barrel in, check fit with a Go-gauge and throw a locking lever to anchor it to the action. As you have already developed loads for the barrel in just a few minutes you are ready to shoot. Or a ring like that on a die. Tighten it down and use a Allen wrench to secure.
Others have done similar. See if any of them are still in here or search for switch barrels.
Should have clarified better. I cut out the aluminum shim providing for the ejector on my bolt faces. You would not need to in your case. You actually don't even need to use a shim as a spacer for no go. It was kind of a generally speaking thing for guys that might be looking for a better alternative to "tape" that was previously mentioned.
The Dunning-Kruger effect is alive and well.
Very good the more we can teach what we have learned, the more our interest in firearms will continue.
Whats you favorite way of fire-forming brass?
Early next week I will be shooting the new build for the first time. Brand new brass. My way of fire-forming has always been to use old bullets that I tried and they never panned out. Ill do a full length resize on the brass and trim to SAMMI Case specs. To save on components I'll load a 3/4 recommended powder load for the type of bullet weight, seat to SAMMI Advised OAL length. Go to a safe place and start firing.
HOWEVER that was usually for hunting loads and not bench except for 4 decades ago. This rifle is my re-entry to bench shooting, looking for any new methods or advise.
All my Savage bench guns run an ejector. If you think you have a lasting condition, your
wasting time picking your brass out. As I'm pulling the bolt back, I already have a round
in my hand to toss in......As for switching out a barrel ?? All mine are shouldered. I just
clamp the barrel in the vise and use an action wrench. If you look real close to the top of
the barrel, you'll see a tiny black punch mark. That's my clocking reference point. It's
what I do......
Keeping my bad Karma intact since 1952
I complain enough about my physical stuff and I told myself the other day no more on public forums. So this will be the last, I hear you Fuj' about picking brass out. I agree 100 per cent. The real reason is I am running no ejector is I just cant bend over well and pluck cases off the ground. Sure I could use a grabber but thats just one thing to take to to the bench.All my Savage bench guns run an ejector. If you think you have a lasting condition, your
wasting time picking your brass out. As I'm pulling the bolt back, I already have a round
in my hand to toss in......As for switching out a barrel ?? All mine are shouldered. I just
clamp the barrel in the vise and use an action wrench. If you look real close to the top of
the barrel, you'll see a tiny black punch mark. That's my clocking reference point. It's
what I do......
Thanks for the idea about the indent on the barrel. Simple but effective.
When I wrote earlier about an invention. I meant no barrel vice, no removal of the action from the stock. Just unlock the locking device and screw the barrel out as the action remains in the stock. Do the opposite to install.
I have an idea if anyone is interested. Its a locking nut with 0.1770 diam. holes drilled around the diameter evenly or based on barrel nut thread. In those holes a locking bar would be used to tighten. (Imagine a winch end with holes and a removable bar for tightening) No torque required as the nut would be set with Blue Locktite snug it and turn 1/8 turn. The barrel would use your method Fuj' with an initial indent marker. The indent would be punched after the owner would set head space of the barrel to the rifles action with the action removed from the stock. Super easy and super fast barrel change.
You still have to apply torque to seat the nut/barrel well against the receiver. You could modify the receiver so you could fit a wrench to it as well, but, many folks like to put on with LOTS of torque. The torque is not to keep it from getting loose, it is to minimize the effect of vibrations between the receiver and barrel.
There have been more ways to make switch barrels than you can imagine. I had two books on gunsmithing, one was for pistols by George Nonte and the other was for rifles by Roy Dunlap. Had info on switch barrels. The problem is you just don't get a good solid joint between the receiver and barrel. Many had sights mounted on the barrel to avoid the boresight shift problem. The lever actions commonly followed that path, but, you don't get 1/4MOA out of common lever actions either.
Sorry, I edited this a few times to try to make it clear.
Ejectors. If I shot competition I'd use an ejector as well, but, I don't. I remove mine so I don't 'miss' the case as it is ejected. Don't mind plucking it out as I try and keep my rate of fire pretty slow. Shoot, open bolt, remove case and inspect it, put back in block, check shot location with spotting scope, mark shot POI and vel on my log, sit for a minute, check wind, then get next round out and go again.
I could write for weeks on as you described on Harmonics by Induced Vibration.. Bottomline its a huge topic.
However, I have thought that every person that uses a tuner (barrel tuner) shall have an accelerometer to calibrate the tuner to the load. No different than than using a chronograph. Except IMHO the accelerometer equals velocity and ballistics.
They are easy to use and build just ask the model helicopter folks. In fact a person could easily build one here and adopt it to your tuner. https://blog.ammolytics.com/2019-01-01/project-cheap-rifle-accelerometer.html The only thing for a barrel is IMHO you need a 6 axis accelerometer for complete tuning and that would require the addition of magnetometer to the hardware. To mount do what I did in a past life, mount the accelerometer to the barrel with a stiff hot glue for stainless or magnetic for carbon based barrels. If your barrel would have front sight holes that would be ideal.
Just attach, simply shoot and then look at the result. Turn the tuner a few degrees and check the results. Keep doing this until the tuner goes from a large sinusoidal wave to the smallest one possible. Baseline is a static rifle with a round loaded and bolt closed.
Photo below courtesy of AMMOLYTICS https://blog.ammolytics.com/about/
Sounds familiar. I was a test engineer for high energy lasers and effects testing. We used rate of acceleration dynamics to point the laser at the targets (long ranges) with feedback from the IR and visible sensors coupled to the tracking software (which was programmed in house). The laser system had a multi-axis active boresight system as well that used high frequency steering mirrors (which were also water cooled to deal with the heat load).
Interesting that no one has definitively shown what happens to a barrel as the bullet travels down the bore. Am also not aware of anyone using really high speed cameras to show the barrel motion during that time. Plenty of stuff for after the projectile leaves the barrel, just not during, probably due to the very small deviations involved.
The 'easy' way out is to just do 'calibrated' testing on target. The dynamics of the barrel show up in group sizes when the muzzle velocities are comparable. Tuners are just another way to 'manage' the group sizes.
All of that is why the switch barrel idea has problems when you get to the smaller groups. The barrel harmonics are inconsistent.
IMHO the below video is the best way I have found on the net to control barrel frequencies and secondary harmonics. Not with just one good looking damper (or tuner) near the crown, but with several dampers applied along the barrel length.
The below method I described should be used used as there are many variables with just shooting to tune a barrel.
The action and barrel are in a static position.A start would start by measuring the frequency or secondary harmonics from a tuning fork applied at the beginning of the lands. Measurement would be with electronic measuring device. The next step is to apply the dampers on the barrel, take a measurement and do it again and agin until the frequency implied by the tuning fork is as low as possible.
Last edited by LDSILLS; Today at 07:08 PM. Reason: edited to clarify my thoughts
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