djosselyn311
Regular
- Location
- Lawrencetown, NS
I am thinking of switching out the barrel on my 455 from .22 to .17hmr. Does everyone use go/no go gauges to confirm headspace? What torque do you use for the barrel screws?
CZ 455 barrel swap
- Thread starter djosselyn311
- Start date
Most people do not usually have a go/no go gauge and simply change barrels. The torque given by Rabid is what to use for the barrel retention screws.
If you have a rifle that was purchased as a "combo" with two or more barrels with matching serial numbers you COULD be good to go. CZ supposedly checks head space before packing the rifle and barrels for sale as a matched set. I can't say for sure, my rifle was bought as a .22LR, not as a combo. Are there any instructions that came with your rifle?
If the new barrel was bought separately it should be checked.
Some 455's are on the loose side of the tolerance apparently, mine is actually fairly tight at 0.046" for a 22LR. As I recall, .22LR is from 0.043"-0.051". I could be wrong about that, check your numbers.
Go/No go gauges are available from several sources in Canada, I've had good luck buying from Big Horn Sales in BC.
If the new barrel was bought separately it should be checked.
Some 455's are on the loose side of the tolerance apparently, mine is actually fairly tight at 0.046" for a 22LR. As I recall, .22LR is from 0.043"-0.051". I could be wrong about that, check your numbers.
Go/No go gauges are available from several sources in Canada, I've had good luck buying from Big Horn Sales in BC.
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I would actually consider your headspace a little loose, Chilly. 0.043" is GO, 0.046" is No-Go, and 0.051" is Field (reject). Failing No-Go doesn't necessarily mean the rifle is out of spec, but it does mean it should be looked at as approaching Max spec is the dangerous condition that leaves too much of the casing unsupported outside of the chamber, risking blown casings. Being within the SAAMI specs is only for safety considerations, and ability to accept any manufacturer's ammo, but is ignorant of accuracy considerations. My custom build was headspaced at 0.0405"
Slight crush fit on most rims, still a touch loose on Eley, and forget about chambering thunderbolts 
(some of those rims are 0.044"-0.046").
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djosselyn311
Regular
- Location
- Lawrencetown, NS
My .22 was bought first, then I got a great deal on a 455 combo so I sold the second rifle and kept the magazine and the 17 hmr barrel. I habe never heard of Big Horn sales, I'll check them out! Thanks for your response
I started with a .22 barrel purchased a .17hmr after the fact and have swapped them in and out a few times with no concern of headspace. Has anyone found the headspace at an unacceptable tolerance yet? You would have read by now if someone had issues...
They aren't the easiest folks to get contact info for.. Gary Eakin is the owner, 250-845-2201, email is thereamerguy@yahoo.ca
I found them when I was looking for go/no go gauges for a 308, they also sell barrels, reamers, all kinds of stuff. Nice guy to deal with.
- Location
- Muskoka, Ontario
I used plastigage to check the headspace on my cz 455 barrels. It was only a few bucks at CT. Here's a link explaining the procedure. http://www.rimfireaccuracy.com/Forums/showthread.php/2506-HEADSPACING-slightly-different-approach
- Location
- Muskoka, Ontario
I found it (plastigage) at Canadian tire in the automotive section. I believe it is used for checking the valve or cylinder clearance on an engine. If I remember correctly it was around $10 which gives you enough to check multiple barrels for headspace. It worked pretty slick when I did it.
You should be able to find plastigage in any half decent automotive supply store...
This method of checking head space may not be as accurate as using a depth micrometer but I find it to be an inexpensive way of verifying that you are "within the range".
You can order headspace gauges from a number of sources. Brownell's quoted Manson Go and No Go shipped to Canada at about $110 CAD. They also have a set that is a little less expensive by about ten dollars.
I did the same thing as you, the .17 HMR barrel fit right at minimum spec (which I consider a good thing, preferable to max spec). I have heard of an issue once posted on RFC with a Lilja barrel in .22 WMR I believe, the owner could not close the bolt on a cartridge, he solved it by lapping his bolt handle until it would close on the cartridge. It's probably not a common occurrence, most should fit within spec but anything is possible.
Yikes! I found my depth mic on Kijiji for $50.
Can you find Go/No Go gauges for less than $110 CAD in Canada? That's was my point. Not everyone can count on experiencing your good fortune on Kijiji and may be satisfied with simple quality Go/No Go gauges that will reveal whether headspace is within specs.
- Location
- West Quebec
Thanks I will look for one for my 455
I never looked at buying a gauge set since I needed to get precise measurements for my projects, and I was prepared to pay $100-$150 as that is what depth mics are selling for on average. Really, one needs more than two gauges because closing the bolt on No-Go doesn't mean "out of spec", it means "look closely at me, I might be out of spec" and then one would check with a Field gauge to see if headspace is less than max spec, or dangerously high. What is the cost to purchase all three gauges? For what is essentially a one-time-use item for a single rifle, if we are to evaluate the utility of gauges for the average rifle owner objectively, are they practical and of reasonable cost? It is an option, and if one is comfortable spending that sum then by all means purchase a headspace gauge set.
There are other options to check this at a lower cost. One can call around to local gunsmiths and even machinists (who will have depth mics) and ask for a quote to measure headspace, it'll take them less than 5 minutes and I'd be shocked if they wanted more than $40 for the work.
If one happens to reload for centerfire, they likely have calipers and possibly a bullet comparator attachment. This can be used to measure rims from bulk ammunition such as Thunderbolt which is highly variable and can be found as high as 0.044"-0.046". With the bullets pulled from measured casings, they can now be used as Go gauges by removing the striker and spring, then gently closing the bolt until resistance is first detected.
FWIW, a quick search on Kijiji for Ontario shows two listings for depth mics at $75, assuming they'd ship nationwide for $15, the tool still comes in at a lower cost than Go gauges and can be used for other tasks than just headspace measurement. *shrug* My point is that the gauges are probably the most expensive and least useful option one could go with.
Oh, I do know where one could get just a .22 LR Go gauge in Canada for less than the cost of purchasing one from Brownells. Interested persons can PM me for more information.
I never looked at buying a gauge set since I needed to get precise measurements for my projects, and I was prepared to pay $100-$150 as that is what depth mics are selling for on average. Really, one needs more than two gauges because closing the bolt on No-Go doesn't mean "out of spec", it means "look closely at me, I might be out of spec" and then one would check with a Field gauge to see if headspace is less than max spec, or dangerously high. What is the cost to purchase all three gauges? For what is essentially a one-time-use item for a single rifle, if we are to evaluate the utility of gauges for the average rifle owner objectively, are they practical and of reasonable cost? It is an option, and if one is comfortable spending that sum then by all means purchase a headspace gauge set.
There are other options to check this at a lower cost. One can call around to local gunsmiths and even machinists (who will have depth mics) and ask for a quote to measure headspace, it'll take them less than 5 minutes and I'd be shocked if they wanted more than $40 for the work.
If one happens to reload for centerfire, they likely have calipers and possibly a bullet comparator attachment. This can be used to measure rims from bulk ammunition such as Thunderbolt which is highly variable and can be found as high as 0.044"-0.046". With the bullets pulled from measured casings, they can now be used as Go gauges by removing the striker and spring, then gently closing the bolt until resistance is first detected.
FWIW, a quick search on Kijiji for Ontario shows two listings for depth mics at $75, assuming they'd ship nationwide for $15, the tool still comes in at a lower cost than Go gauges and can be used for other tasks than just headspace measurement. *shrug* My point is that the gauges are probably the most expensive and least useful option one could go with.
Oh, I do know where one could get just a .22 LR Go gauge in Canada for less than the cost of purchasing one from Brownells. Interested persons can PM me for more information.
Sigh. It's great that you have a depth micrometer. You can't seem to let anything go without some effort at getting the last word or a retort to show off your inestimable knowledge. You've got to learn to accept that you don't need to challenge everyone who says something that isn't the same as what you've said. As the expression goes, there's more than one way to skin a cat.
As I said on RFC, where you also vet my comments, I'm not interested in arguing with you. And, as I said on RFC, if you want to fight think about joining the army or getting married.
