Taped Go-Gauge / No-Go

[Italianusmc_ny]

Hello All,
I just finished rebarreling my Savage with a Barlein Pre-Fit.
When headspacing the rifle, I used a single piece of Blue Painters tape on the rear of my Forester Go-Guage trimmed around the edge.
I removed the ejector plunger but left in the extractor.

Nice smooth close on the go and with the tape the bolt stops 1/4 way down from open position.

Opinions??
I Now open the floor.

 

[gman47564]

Put a new empty case in it now and see if the bolt closes without resistance.. if it closes easy you should be good to go..

 

[K9TXS]

Hello All,
I just finished rebarreling my Savage with a Barlein Pre-Fit.
When headspacing the rifle, I used a single piece of Blue Painters tape on the rear of my Forester Go-Guage trimmed around the edge.
I removed the ejector plunger but left in the extractor.

I've never tried this, but everything I've read in the past I believe folks used clear tape like a Scotch tape that is fairly narrow. Not the clear packing tape either. I think painters tape is thicker than the Scotch tape.

 

[M-61]

Tape on a go/gauge to replicate a no/go gauge

Regular 3M 'Scotch Tape' also called MAGIC tape and Invisible Tape by the same manufacturer.
Only preference I have for this is it seems to be available everywhere. Even though one roll should last a lifetime mine seems to disappear.
Couple thousandths thick.
I agree.....the blue tape is thicker.....I just want to go back to the known roll each time.

 

[Zero333]

Measure the go gauge with and without the tape... the difference should be 0.004".

As long as the bolt doesn't close all the way you are good to go !

I too have 1 or 2 pre-fit barrels that allow the bolt to go down 1/4 of the way with the masking tape on the go-gauge. No problems.


Masking tape is not solid, so as you close the bolt it can smear and move a little, thus giving you the ability to close the bolt 1/4 of the way down.

 

[gman47564]

The blue painters tape is .004 thick..
The difference between my 284 go and no go is .005.. the op should be good to go..

 

[Jeffrey Tooker]

There are those who use two layers of the Scotch tape. It all depends on how tight you want your head space. Savages will head space much closer than a set of head space gauges. I use a new Lapua brass case and two layers of Scotch. With the Scotch tape the bolt should close only part way. Then I resize a fired and check that the bolt closes easily in the resized case. This means that your dies will resize the case to fit the head space. For fire formed cases, resize the FF case in your dies and work from there. I am not responsible others using the method above. This is my way, others may do as they wish.

Jeffrey

 

[Uncle Ed]

For a little more than $30.00 you could buy a NO-GO gauge and not worry if your tape was made in China. And I thought I was a cheap bastard!

 

[Doug Beach]

You’re fine.

 

[Webster]

Put a new empty case in it now and see if the bolt closes without resistance.. if it closes easy you should be good to go..

Had a discussion on hs on the 6br forum. As long as thee hs is close it Doesn’t matter what it was. IF you can chamber a new empty case fire it and properly size what difference does it make if your chamber doesn’t have the same dimensions as someone’s blue print? Jam and shot. You now have a semi wildcat several thou different than the standard spec.

 

[gman47564]

You wouldnt want the case to grow too much.. that can cause thinning of the case at the 200 datum.. and could cause sizing issues with your fl dies.. i try to set mine where the shoulder only blows forward a couple thousands on a new case..

 

[linebaugh]

Good to go. Enjoy your rifle. Set dies to set shoulder back to desired level after first fire.

 

[2506]

The wonders of tape. Here is another use for tape. I used to shoot bench type matches with stock military rifles. Only change in them allowed was you could replace the front sight blade because most of these rifles had a 300 yard battle sighting and they shot way high at 100 yards which was the yardage we were shooting. Rifles like the Mauser's that had ladder style back sights could be adjusted in small increments by placing a piece of tape under the slider on the ladder sight. Each piece of masking tape on average moved 1/4 inch and duct tape 1/2" at 100 yards. My practice was to find the most accurate load for the rifle then with a higher blade front sight I would file it down until my point of impact was 1 inch low at 100 yards then use tape to fine adjust to where my point of impact needed to be on the day of a match. With light, weather etc. conditions how you see the sights and how the rifle shot that day change and this method gave you wiggle room.

 

[wedgy]

Recheck after you tighten the barrel nut as the dimension can change.

 

[riflewoman]

I use a piece of .003 shimstock about 1/4 inch square. I “stick it” to the base of the Go gauge with a tiny dab of grease. Then I press the base to a solid object to squeeze out the excess grease. That adds about 0,0035 to the go measurement. So long as your careful the shim will remain on the base of the gauge for the duration of the measurement.

 

[jelenko]

Wait. In reading the OP, doesn't it says the bolt closes ~ 1/4 the way with a go gauge? => the chamber would be shorter than '0'. Which seems odd given that the go gauge had the tape on the bottom as the barrel was being headspaced.

 

[M-61]

Recheck after you tighten the barrel nut as the dimension can change.

Big time. That's the one step I find a pain. The tightening of the jam nut and then
re-checking only to find it has moved. I've done plenty but never mastered getting it correct with just ONE try. 2 or 3 tries and I'm good to go.
So the re-check is indeed a must.

 

[Webster]

You wouldnt want the case to grow too much.. that can cause thinning of the case at the 200 datum.. and could cause sizing issues with your fl dies.. i try to set mine where the shoulder only blows forward a couple thousands on a new case..

If you jam the bullet on the first firing I see now reason for the case to get thinner at the .200’’ location. I fire form 6br to 6brx .100’’ the shoulder moves a lot. Sounds like your saying all wildcat cartridges would make a defective case.

 

[Uncle Ed]

If you had the Hornady cartridge case headspace gauge you could measure the gauge and again with the tape and see how much longer it is. Just remember tape is soft and a ballpark measurement. And it's not the end of the world if the bolt closes on a NO-GO gauge.

If you look at the SAAMI cartridge and chamber drawing headspace for the average case is listed as Min and Max with .010 between the two.

The average NO-GO gauge is .003 longer than the GO gauge, meaning they are giving you .003 to play with setting up a new barrel. And max headspace is .007 longer than the NO-GO gauge.

Below a Colt AR15 Field gauge at 1.4736

Below my "adjusted" Hornady gauge measuring the field gauge at 1.4735. There is a .011 gap between the red and silver sections of the Hornady gauge.

Below a "FIRED" case from my AR15 in the Hornady gauge, I then set the resizing die for .003 shoulder bump.

And now how much head clearance do your new unfired cases have. I have had new cases .009 shorter than my GO gauge. Meaning will your new cases stretch and thin when fired the first time?

Below a set of nine .308 gauges from GO to Field with no tape. Normally Field gauges are .001 shorter than max headspace. And that's why there are only nine gauges.

The .308 cases below were fired in a new Savage rifle and resized with the die making hard contact with the shell holder. What is interesting in the bottom chart is at what firing the cases actually started to stretch and thin.

 

[6MMsteve]

if you headspace a little tight on the go there is no need for nogo this is how I headspace my savage barrels just a little feel on the go gauge..but then I do put 1 pc of scotch tape on just to be sure.... and it's tight