Go - No go gauges
- Thread starter JesseSVTJaymes
- Start date
I’ve read of guys using a new piece of sized brass as their go, than take a piece of painters tape on the back of it to as 0.002” to it as a no go. I’ve never done it, but I’ve read/seen lots of people on YouTube do it. I believe it was Gavintoob? Do it on YouTube when he built one of his rifles.
- Location
- Fraser Valley, B.C.
You can order directly from Manson Precision and Pacific Tool and Gauge if you want to. Both are fairly good to deal with especially for something that is likely already in stock.
If you don’t want to deal with duties I would recommend Big Horn Sales in BC they are fantastic to deal with and I’ve gotten a few sets from him.
You can also find forster gauges around same with clymer.
As mentioned above you can use a go gauge plus tape. I have tested the method and it works, however I prefer to have both gauges for peace of mind.
Cheers,
B
If you don’t want to deal with duties I would recommend Big Horn Sales in BC they are fantastic to deal with and I’ve gotten a few sets from him.
You can also find forster gauges around same with clymer.
As mentioned above you can use a go gauge plus tape. I have tested the method and it works, however I prefer to have both gauges for peace of mind.
Cheers,
B
- Location
- Western Manitoba
Any belted magnum is probably the same to each other - whatever specific cartridge that it might say - 7mm Rem Mag, 338 Win Mag, 375H&H are all the same items. I have a set of "JGS" branded GO and NOGO gauges - they are marked as "300 Win Mag", but I am currently using them to fit a 416 Rem Mag, if the reamer ever shows up ... For those cartridges, all you are gauging is the distance from front of cartridge belt recess to bolt face - not gauging the cartridge shoulder or body length at all.
I was looking on SAAMI drawings - they appear to define Minimum length - which is "GO" gauge. They appear to define Maximum length - which is "FIELD" gauge. I can not find where SAAMI defines NOGO gauge - it might be a barrel maker or gauge maker invention - often or usually 0.004" longer than a GO gauge. Maximum, as per SAAMI, is often 0.010" longer than GO gauge. I think if you fit a chamber so the bolt will close on GO, and not close on NOGO - or at least that you can feel the NOGO contacting the chamber - then you are closer to Minimum chamber, than you are to Maximum chamber. Lap the rear of the bolt lugs, crush the bolt lug seats in the receiver, and so on, and you will change your "end-play" dimension.
I no longer buy "sets" of gauges - I just buy "GO" gauges. At Canadian Tire or similar, I bought a set of feeler gauges, and cut out a series of shim circles about 0.450" or so from various thicknesses - I think I have from 0.003" to 0.012". A small dab of grease on bolt face will "stick" the shim there - then use a GO gauge - so with a 0.004" shim on bolt face, will be very close to a NOGO gauge. Any excess grease will simply squish out, I am told.
I was looking on SAAMI drawings - they appear to define Minimum length - which is "GO" gauge. They appear to define Maximum length - which is "FIELD" gauge. I can not find where SAAMI defines NOGO gauge - it might be a barrel maker or gauge maker invention - often or usually 0.004" longer than a GO gauge. Maximum, as per SAAMI, is often 0.010" longer than GO gauge. I think if you fit a chamber so the bolt will close on GO, and not close on NOGO - or at least that you can feel the NOGO contacting the chamber - then you are closer to Minimum chamber, than you are to Maximum chamber. Lap the rear of the bolt lugs, crush the bolt lug seats in the receiver, and so on, and you will change your "end-play" dimension.
I no longer buy "sets" of gauges - I just buy "GO" gauges. At Canadian Tire or similar, I bought a set of feeler gauges, and cut out a series of shim circles about 0.450" or so from various thicknesses - I think I have from 0.003" to 0.012". A small dab of grease on bolt face will "stick" the shim there - then use a GO gauge - so with a 0.004" shim on bolt face, will be very close to a NOGO gauge. Any excess grease will simply squish out, I am told.
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0.002 as a no go isn't particularly generous margin. .002 is more like scotch tape. Painter's tape is around .005 and would be normal clearance for some cartridges for a no go.
Using a cartridge case and tape isn't helpful unless the actual exact thickness of the rim/belt is known. Cartridge cases vary. Also, the tape or shim thickness must be carefully measured. Then there is the possibility of compression to consider.
Actual steel gauges are best.
Actual steel gauges are best.
- Location
- Western Manitoba
I think the fallacy with that is the assumption that all brass cases are made the same - they are not - they will be made with a plus or minus tolerance. If you are going to try to "make do" with that idea, instead of using precision ground steel gauges, then take the time to do up five or six or 10 new brass cases and check with all of them.
If you are hand loading and properly sizing your cases to match that chamber - it makes about no difference - your cases will fit. Is when you want to use factory ammo that you will get tangled up within SAAMI (or CIP) specs.
SAAMI defines a Minimum and Maximum dimension for cases - commercial producers have to be within that - anywhere - you will not know without measuring. And is "tiny" stuff - the difference between too long and too short is often 0.011" - eleven thousandths of an inch. The difference between a GO and a NOGO gauge is often 0.004" - 4 thousandths of an inch - often the thickness of a piece of computer printer paper. A new brass case has to fit between Minimum and Maximum to be SAAMI compliant - that is a 0.010" range. The GO and NOGO gauges here are stamped to 4 decimal places for their length - .2200 and .2240, so I presume their tolerances are in the 10-thousandths of an inch - at least 10 times more precise than brass cases are made - I do not know precisely what the tolerances are for ground headspace gauges.
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Not entirely true. I know the 450 Marlin uses a different belt than the "standard" not sure if its the only one or not though.
- Location
- Western Manitoba
Yep! And there are probably others that differ, as well. However, most that had 375 H&H or 300 H&H as parent, are likely the same. 450 Marlin is an example of a case that did not evolve from that. I never played with them, but I understand there are some big belted Weatherby cases that differ as well.
As I understand it, original belts were used to provide a dependable "stop" for cases that had long tapering shoulders that were not dependable for that - it became associated with "magnum" - from the days when "customer always right" - so makers would produce what customers wanted. In time, it was discovered that the belt did not make the case stronger - despite "customer's opinion" - and newer cases, without the belt, were created - that had similar or greater performance compared to their belted predecessors. The newer cases headspace on their shoulder - which many canny reloaders do with belted or rimmed cases anyway - ignoring the belt or rim completely, for "end play" purposes.
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Thank you all. I found the ones back ordered on RDSC and called them regarding timeline. "Id be lying to you if I gave you a date" was the answer I recd.
I am in no rush, I just ordered my barrel yesterday. I just want to know when the barrel gets here I am G2G
Jesse
I am in no rush, I just ordered my barrel yesterday. I just want to know when the barrel gets here I am G2G
Jesse
This is wildly inaccurate.
Brass cases are soft and tape is also soft so it is easy to miss the gauge. Also, relying on a sized case means the rifle is being built to whatever the sizing die is set to. Could be SAAMI, could not be? Who knows.
As shooters we spend a lot of time discussing rifle BOOMS and endlessly debate the difference between 223 and 556 and yet apparently we cheap out on the one tool that will ensure a properly headspace rifle. Seems like a silly thing to try to save money on.
- Location
- Western Manitoba
I am a home-guy - not a gunsmith - likely I am Bubba with Capital "B". I just finished to screw on a Mauser 98 receiver onto a barrel that had the chamber slightly deepened by the previous owner - that required me to peel a smidgeon off the barrel shoulder and the rear end of the barrel to fit this receiver and this bolt. A Clymer GO gauge was used - I can feel it as the bolt closes. 5 x new R-P brass allow that bolt to fully close. 5 x W-W new brass also allow that bolt to close - two of them with no feel of contact at all. But some re-sized brass - labelled by me as re-sized in Oct 2022, do not allow the bolt to close at all - looks like I have some re-sizing fussing to do, to actually match to new brass. And of the 10 pieces of new brass that I used - 2 brands, two of them were different than the others.
My "so-called" re-sizing was done with RCBS Full Length dies that I have used at least 15 years - those cases had been previously fired in a rifle that I no longer own - but I had reloaded for it, many hundreds of times, using those dies and that shell holder - was just fine in that previous rifle - this one will be a bit more fussy.
My "so-called" re-sizing was done with RCBS Full Length dies that I have used at least 15 years - those cases had been previously fired in a rifle that I no longer own - but I had reloaded for it, many hundreds of times, using those dies and that shell holder - was just fine in that previous rifle - this one will be a bit more fussy.
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