BMWR12 35 Posted December 8, 2013 My rifle works good the way it is now but I want to change out the bolt to the correct maker/date. I have the bolt dissassembled and have a set of headspace gauges. Is it a straight forward as the link says or are there problems I can run into.?http://www.odcmp.org/0309/default.asp?page=M1HEADSPACE Quote Share this post Link to post Share on other sites
usnmars 136 Posted December 9, 2013 Its straight forward, the article says it just as it is. Just make sure the lugs go in the notch 100% on a go gauge Quote Share this post Link to post Share on other sites
BMWR12 35 Posted December 9, 2013 I will give it a try next week. I also have to install a type 2 lockbar sight that is not here yet. Quote Share this post Link to post Share on other sites
BMWR12 35 Posted December 9, 2013 Does this look good? Thanks Pic 1 is with Go gauge Pic 2 with NO Go gauge Quote Share this post Link to post Share on other sites
usnmars 136 Posted December 10, 2013 Yuppers. Looks like its happy Quote Share this post Link to post Share on other sites
Old School 611 Posted December 10, 2013 +1 Do you have a field gauge Nick - Unless you just want to borrow it...Why would he need a "field" gauge if it doesn't close on a "no-go"? Quote Share this post Link to post Share on other sites
BMWR12 35 Posted December 10, 2013 +1 Do you have a field gauge +1 Do you have a field gauge I do not have a field gauge. There is a decent sized gap with the NO Go gauge in, it is hard to see from the angle in the pic. The cmp says the bolt should not be able to rotate fully into battery and there should be a gap beneath the right lug of at least the thickness of a couple of business cards. The gap on mine is less than the one the CMP has pictured though. I guess it would't hurt to buythe field gauge. Quote Share this post Link to post Share on other sites
Old School 611 Posted December 10, 2013 I don't think you have to....I have a M1917 that has just about the same closing on a no go....and I am fine with that......... I would venture a guess that the lug gap on a field gauge * IS * going to be much more and as such the rifle is fully serviceable in terms of headspace....it would just be something to correlate against...etc...NOT mandatory...she looks good to go...have at it !! Just to clarify....A "GO" gauge gives you minimum allowable chamber dimension. So the longest case encountered in ammunition reloading standards, such as SAAMI, will chamber. A "NO GO" is the maximum allowable chamber dimension. As long as the bolt doesn't fully close you're good to go. "FIELD" indicates an excessive chamber dimension and should not be fired. Nick - I you were building a new rifle, rebarreling or rechambering I would want a "GO" gauge to allow the bolt to close and a "No GO" to close about 60-75% A "FIELD" gauge is nice to carry around when buying a used rifle. Quote Share this post Link to post Share on other sites
BMWR12 35 Posted December 10, 2013 I just took apart both(HRA and SA) bolts and checked them with the gauges. The gap between the Right lug and the reciever is 0.042" for both bolts. Do you guys know how to check the headspace on a 03a3? I can't find any real info on how to do it properly? I have been offered quite a few US .30cal rifles this year and I need to learn more about them before I buy them. Quote Share this post Link to post Share on other sites
BMWR12 35 Posted December 11, 2013 BTW head space is good on the SA bolt....if that is the replacement...BTW what is the info on the HRA bolt....if you intend to part it out.... Not markedly different...... strip bolt....place head space gauge in chamber...try to close bolt...if close all the way..no good...if only partially closes....well your good... BUT also check the go gauge as well..should close fully. If you want to know stuff about 03's.... buy brophys book and /or campbells...I have both..invaluable information.... I LOVE 03's !! and A3's... I don't own a real A4 ...I have a 'clone' but it is a tack driver... SCOOP EM UP ! PS: If you dont want any KEEP ME IN MIND ! I know the headspace is good. The HRA bolt is a complete 6528287 marked with U It is not the D6528287. I don't know what I am doing with it yet. These seem to be harder to find and cost twice what a Springfield does for what I have seen. Quote Share this post Link to post Share on other sites
Porthole 15 Posted December 11, 2013 Have any of you ground out the relief in the gauges so the bolt doesn't have to be disassembled? If so, any issues with that? Quote Share this post Link to post Share on other sites
1563621 388 Posted December 16, 2013 HRA bolts sell for 85.00 on CMP web. Quote Share this post Link to post Share on other sites