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Old October 14th, 2018, 09:23 PM #1
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Headspacing with spent cartridge

I have a Savage Model 12 with a wildcat barrel installed. Took it to the range for its maiden voyage and was having multiple light primer strikes. After using a comparator between a factory round and a spent casing, the difference was 0.013, which tells me I have a headspace problem.

As this is a wildcat, a Go gauge is expensive and rather difficult/time consuming to come by. I have been told and read on a few pages that you can take a spent case, apply a single layer of scotch tape (which has a thickness of 0.0025" thick), insert into the chamber and run the action onto the barrel until it just touches and then tighten the barrel nut back up and it should be GTG.

Has anyone else heard of or done this?
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Old October 14th, 2018, 09:42 PM #2
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Iíve heard about it. They named scotch brand because it was consistent. More of a make shift head space
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Old October 14th, 2018, 09:44 PM #3
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Although it's not the best, correct, or probably even an acceptable way to do it, people have checked or set headspace with an unfired cartridge and tape. However, a spent cartridge has expanded to fill the chamber that it was fired in and cannot be used for this purpose.
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Old October 14th, 2018, 09:58 PM #4
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As a wildcat, don't you have the luxury of simply adjusting your die to the chamber and leave it at that? Certainly you're not re-headspacing a rifle to match a die setting....are you?

Even when loading for a standard cartridge, the die can create an excess headspace condition. The manufacturer's "boiler plate" die setting instructions are not usually optimum for anything but the absolute SAAMI minimum chamber.
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Old October 14th, 2018, 10:24 PM #5
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Quote:
Originally Posted by E.Shell View Post
As a wildcat, don't you have the luxury of simply adjusting your die to the chamber and leave it at that? Certainly you're not re-headspacing a rifle to match a die setting....are you?

Even when loading for a standard cartridge, the die can create an excess headspace condition. The manufacturer's "boiler plate" die setting instructions are not usually optimum for anything but the absolute SAAMI minimum chamber.
The ammo I have was manufactured by someone else that loads for this caliber. I have not started loading my own yet and likely will not be set up to load for several months yet.
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Old October 14th, 2018, 10:35 PM #6
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just out of idle curiosity, what is the wildcat? Someone here may have a headspace guage set and might be able to help you out. I have a couple wildcats myself. The only one I don't own gauges for, I don't have to worry about as the chamber was cut precisely to spec and the dies were made exactly to match. That barrel is also shouldered and thus not adjustable.

If you do plan to "set" your own headspace on a nut type installation, I would not use a fired case. As Ed says, that is going to make a bad situation worse. You would need to use an unfired case with either scotch tape or packing tape on the case head. strip the bolt head of ejector and extractor when performing these operations.
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Old October 14th, 2018, 11:49 PM #7
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Quote:
Originally Posted by 4g64loser View Post
just out of idle curiosity, what is the wildcat? Someone here may have a headspace guage set and might be able to help you out. I have a couple wildcats myself. The only one I don't own gauges for, I don't have to worry about as the chamber was cut precisely to spec and the dies were made exactly to match. That barrel is also shouldered and thus not adjustable.

If you do plan to "set" your own headspace on a nut type installation, I would not use a fired case. As Ed says, that is going to make a bad situation worse. You would need to use an unfired case with either scotch tape or packing tape on the case head. strip the bolt head of ejector and extractor when performing these operations.
.277 Wolverine

Just had a chat with the developer. He says the loaded ammo is designed to headspace with an AR and Savage rifles need minimal headspace. He recommended around 0.003" and said I should use 2 pieces of scotch tape on an unfired cartridge and screw down until it firmly seats against the round as 2 pieces of tape is 0.0045".

I had removed the ejector, but left in the extractor to hold the round in place. Would this affect the end result?
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Old October 15th, 2018, 09:16 AM #8
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I honestly think you're backing into this and doing it the hard way. I really want to say "wrong way", but maybe that's a bit strong.

First off, .0045" is nothing near "minimum" headspace and the person yoiu spoke with should know this. You are going to create case head separations with very few firings if you maintain such a large clearance. "Minimum" headspace is something like .0015" to .002" - just enough to chamber smoothly, even with a little fouling.

Ammunition headspace requirements are either a) no different from one rifle to the next, or, b) in practice, slightly greater clearance for the AR-15, which depends on spring tension to go fully into battery. There is NO headspace spec that applies only to Savages and ARs and not to everything else.

Do you suspect your rifle to be faulty? Was the barrel installed by someone who didn't know what they were doing? If so, then it might make sense to match your friend's rifle (not necessarily his ammo).

What is the headspace dimension with this ammo in your friend's rifle? His ammo may also be marginally short in his own gun, just not quite short enough to misfire.

Is your friend supplying all of your ammo, or just enough to get you out to the range once or twice? Otherwise, setting up your rifle to match your friend's die setting, which is still not necessarily right, even for his own rifle, doesn't make sense at any level, unless he is providing you with all of your ammunition.

Wildcats, especially, and even factory-supported cartridges, can and will vary from what we would call "minimum" to what would be "maximum". If your rifle is correct and his is too tight, or if his dies are set to provide too much shoulder setback, you will be maladjusting your rifle. The good news is that wildcats are loaded to individual rifles and your maladjusted rifle won't come to a point of failing to chamber a corrected configured factory round.

In teaching the precision handloading classes, I very often see dies, even for factory ammo, set to deliver too much shoulder setback. This usually comes from setting the dies to the manufacturer's generic, cover-my-own-butt directions. These directions are intended to provide minimum length ammo so that it will chamber smoothly, even in an SAAMI minimum chamber. Minimum length ammo is seldom what is actually needed for any given rifle, and VERY few rifles are ever set to minimum, except custom match rifles. Most custom match rifles are very close to minimum and this is about the only place the die maker's directions will deliver well-fitted cases.

Setting your own dies for a wildcat or factory cartridge is very straightforward, especially with the .277, because the shoulder of the parent case gets set back. Were this my rifle, I would disregard your friend's ammo and load my own from the beginning, tailored to fit my own rifle. Set you sizing die to be just up off the shelholder, so you are still not sizing enough to chamber. Use a fresh .223 case, run it into your sizing die, cut it off as required, and try to chamber it. If it won't chamber, good. Adjust your die in about 1/4 turn at a time, test fit and try it in the chamber until you get it to chamber freely. Grab another new case and size that one once with your new die setting and make sure it works. At this point, I would make tiny die adjustments until I found the exact "zero" headspace point, then plan for about .002" clearance.

Maybe this will be of help:
http://www.shell-central.com/Brass_Prep1.html
I suspect your ammo is going to want to be at about a "Level 2" fit.
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Old October 15th, 2018, 09:30 AM #9
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I am not going to have the capacity to load my own ammo until spring, at least. So, I buy all of my ammo currently from http://www.jbsfirearms.com/category-s/1831.htm He has admitted that he uses CCI 450 primers instead of 400 that most Savage loaders use.
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Old October 15th, 2018, 10:04 AM #10
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I just looked, and found several references to the difference between a Go and a No-Go for .20-06 to be 0.004 inches.

So 0.0045" is not excessive. 0.045" would be HUGE.

Another site states the benchrest/match gauges are about 0.004" and regular gauges at 0.006"-0.008".

Another one states that the SAAMI spec for the difference between Go and No-Go is 0.0035".
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