I have a no1mk3* that shoots beautifully, but has some headspace issues. The primers push out a bit, and some brass have a distictive ridge in them. No failures, but why push it. I have another un-used bolt head, but it measures almost exactly the same (within one-thou "). I've heard spare bolt heads were marked with a "S" and were longer, you would sand to fit. Yea or nay? Marstar's site has boltheads, but asks for measurement. How do I measure something I don't have? Mine are too small. Can someone point me in the right direction?
Headspace fixes? How to order the proper bolthead?
- Thread starter 5440fight
- Start date
- Location
- Pile of Bones, SK
Your best bet is to take it to a gunsmith to have it done. The alternative is to order a bunch of different sizes of No1 bolt heads and change them out until one works.
Thanks, but I was looking for an answer, not a gunsmith.
I am not aware of No 1 MK III's having different length bolt heads the the No 4's did.
I have see the S on some of the bolt heads but can find no ref:as to why.
In that action, the action stretches and or the barrel threads compress and of course the bolt locking lugs wear and this causes the headspace issue you are seeing. The cure is to remove the barrel, turn off 1 whole thread, reshoulder the barrel and rechamber.
Please let me know if you find out the the S mean larger, that would be news and be very interesting!!
Scott
I have see the S on some of the bolt heads but can find no ref:as to why.
In that action, the action stretches and or the barrel threads compress and of course the bolt locking lugs wear and this causes the headspace issue you are seeing. The cure is to remove the barrel, turn off 1 whole thread, reshoulder the barrel and rechamber.
Please let me know if you find out the the S mean larger, that would be news and be very interesting!!
Scott
No. 1 MKIII bolt heads were not made in different size like the No4 was. Like it was suggested above you can take it to a Gunsmith with a good supply of No.1 boltheads, sometimes from one manufaturer of boltheads to the next there is enough play in the specifications (made by many over a long time period) to compensate for some light headspace. Otherwise, the barrel has to be set back or replaced.
The distinctive ridge on the fired case is not headspace related. It is formed when the case diameter expands to fit the chamber.
Are you getting incipient separations?
Protruding primer could indicate excess headspace. Whether it is sufficiently excessive to cause a problem, hard to say.
You need to check with gauges.
There are other methods that can be used as well.
Fire a primed case (no powder or bullet). Measure primer projection, add rim thickness. You will need preceision measuring tools to do this.
Minimum breechface to boltface dimension is .064". Maximum is on the order of .074". Best if it is toward the lower end.
If you handload, you can prepare ammunition so that the distance from the barrelface to the boltface is irrelevant. The round headspaces on the shoulder.
If you want to start swapping boltheads, its best to get a sack of them and keep trying them until you get one that gauges within the limits. Boltheads are not entirely interchangable, how the bolthead screws into the bolt body is important. The threads do not take the load.
Personally, if it were my rifle, and if it accepted a Field gauge, and none of the bolts or boltheads in my supply corrected the problem, I would just produce appropriate handloads.
Are you getting incipient separations?
Protruding primer could indicate excess headspace. Whether it is sufficiently excessive to cause a problem, hard to say.
You need to check with gauges.
There are other methods that can be used as well.
Fire a primed case (no powder or bullet). Measure primer projection, add rim thickness. You will need preceision measuring tools to do this.
Minimum breechface to boltface dimension is .064". Maximum is on the order of .074". Best if it is toward the lower end.
If you handload, you can prepare ammunition so that the distance from the barrelface to the boltface is irrelevant. The round headspaces on the shoulder.
If you want to start swapping boltheads, its best to get a sack of them and keep trying them until you get one that gauges within the limits. Boltheads are not entirely interchangable, how the bolthead screws into the bolt body is important. The threads do not take the load.
Personally, if it were my rifle, and if it accepted a Field gauge, and none of the bolts or boltheads in my supply corrected the problem, I would just produce appropriate handloads.
- Location
- Pile of Bones, SK
See second part of my reply then! 
Actually, taking into account from your post you only indicate that you measured the bolt heads, but said nothing about measuring the actual headspacing. Start by getting a set of guages, learn how to measure headspace properly, if there actually is a problem: then go to a gunsmith if you're too cheap to pick up some spare bolt heads.
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Pulling the barrel, setting it back one thread, and recutting the chamber can be a fix. I've done it. You can get really tight headspace. If this is an issue rifle, it will affect everything foreward of the receiver. If it is a sporter, there are fewer complications. There would be significant expense, and unless the bore is perfect would be a waste of time and money.
Rebarrelling with an issue barrel would be a crapshoot - you have no way of knowing if it will cure a headspace problem until the gauges go in after the barrel is on.
Rebarrelling with an issue barrel would be a crapshoot - you have no way of knowing if it will cure a headspace problem until the gauges go in after the barrel is on.
I have an Ishapore SMLE that closes on a no-go gauge. I never checked the field gauge as I don't have access to one - hotter load resulted in some head separation - however the brass was of unknown origin.
Milder loads (35gr of RL-15 with 174gr Hornady FMJ) worked fine.
Milder loads (35gr of RL-15 with 174gr Hornady FMJ) worked fine.
As Tiriaq mentioned, you dont necessarily have a headspace issue, and replacing the bolthead is not a cut and dried affair.
I've never seen an S marked head. If you want to persist, add 3 thou (in inches) to your measurement and forward that to Marstar as the required measurement.
I've never seen an S marked head. If you want to persist, add 3 thou (in inches) to your measurement and forward that to Marstar as the required measurement.
Thanks to all the answers, this is what I had in mind. My local gunsmith doesn't even have a set of gauges
, says someone ran off with them...I'll order a set from Gairlochen (sp?). Is the "ridge" from case expansion an issue of safety? Some were only mildly distorted, but a few looked and felt iffy- almost looked like a crack- almost. This was with 180 grain winchester silver box, not reloads. The rifle is in full wood, and has the original barrel (matches action, stock, and nosecap) bolt is mismatched.
The "S" on the bolt thing was something I read online today, then again I read that Michael Jackson is still alive and living with elvis too...
I'll post pics of the brass tonight.
I bought 3 gauges from Gairlochian, and my life is a lot simpler now.
I also gather bolt heads whenever I see them (at a reasonable price...) so I have a few spares of different lengths, plus my gunsmith has some too, so usually I can solve headspace issues.
Lou
I also gather bolt heads whenever I see them (at a reasonable price...) so I have a few spares of different lengths, plus my gunsmith has some too, so usually I can solve headspace issues.
Lou
Actually, taking into account from your post you only indicate that you measured the bolt heads, but said nothing about measuring the actual headspacing. Start by getting a set of guages, learn how to measure headspace properly, if there actually is a problem: then go to a gunsmith if you're too cheap to pick up some spare bolt heads.
No offence, but my pet peave is when someone says take it to a gunsmith. (Gee, I was gonna take it to a vet I know, did a great job on the cat...)
But when I see some of the patient, complete answers here, I see where you're coming from. If someone knows a good milsurp smith in the lower mainland let me know, that way if it's a issue I can't deal with, I'll know who to see.
- Location
- Pile of Bones, SK
One of my pet peeves is someone dumping on you for giving them advice when they asked for it.
I didn't say "take it to a gunsmith" just because, I said it because that would be the easiest, fastest and probably the cheapest solution in this case. I didn't elaborate more than that because this topic seems to come up every other week. Anyway, it sucks that your local smith is lacking some pretty basic tools though, I feel your pain. Good luck with getting it sorted.Check out some of the posts by bigedp51, good stuff:
http://www.canadiangunnutz.com/forum/showthread.php?t=414191&highlight=headspace
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One of my pet peeves is someone dumping on you for giving them advice when they asked for it.
Check out some of the posts by bigedp51, good stuff:
http://www.canadiangunnutz.com/forum/showthread.php?t=414191&highlight=headspace
I searched here using "headspace, no1mk3, ect... and came up with little, milsurp knowledge library (it is a little intimidating, HUGE amount of info, where to find what I want) and three or four other sites first, but what tiriaq, lou and few others offered could have saved me hours of reading. Anyhow, I know you meant well, maybe I had sand in my panties after my hours of searching...
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Moving on. pics:
Obviously I've chosen the worst culprits. On close inspection, I notice that the worst of the primer distortion matches the nasty pitting on the bolt face.
Maybe if I use that nice shiney one I just bought, the issue will lessen.
All cases have a visible "shiney" ring, but my other Lee's (no4, no5...) do this a bit too. A few (pictured here) have a distict ridge that you can feel and see. Worse on one side than the other, making some cases "out of round".
Obviously I've chosen the worst culprits. On close inspection, I notice that the worst of the primer distortion matches the nasty pitting on the bolt face.
All cases have a visible "shiney" ring, but my other Lee's (no4, no5...) do this a bit too. A few (pictured here) have a distict ridge that you can feel and see. Worse on one side than the other, making some cases "out of round".
- Location
- Pile of Bones, SK
http://4.bp.########.com/_0zJ3UAMKj4c/Sx6JsBO3SHI/AAAAAAAACtQ/6GNmqqOKFMI/S1600-R/smooch.jpg
Wow, that bolt head is buggered, even the extractor is chipped. I'm going to shut up and learn something now.
Wow, that bolt head is buggered, even the extractor is chipped. I'm going to shut up and learn something now.
Looks as if you have incipient separations on some of that brass. In the bottom photo, the two cases where the heads are visible, plus another in the upper photo...
Looking at the case, you see the unexpanded solid head, then there is the expansion ring in the transition zone. About 1/16" further up, there is a frosted ring. There may be a matching groove running around the inside of the case. Use a good light, or make a little right angled probe from a paper clip, or section the caseheads. If there is a groove running around inside the case, that is a separation about to happen.
This is not unusual, but if it is occurring, don't reload any cases in this condition. They will fail.
It is necessary to inspect .303 brass fired in Lee Enfields carefully, and cull as required.
Your primer protrusion isn't as bad as some. That boltface pitting is ugly.
I suspect that your rifle is on the loose side, as many Lee Enfields are. Tightening up the headspace would not be a bad idea.
Looking at the case, you see the unexpanded solid head, then there is the expansion ring in the transition zone. About 1/16" further up, there is a frosted ring. There may be a matching groove running around the inside of the case. Use a good light, or make a little right angled probe from a paper clip, or section the caseheads. If there is a groove running around inside the case, that is a separation about to happen.
This is not unusual, but if it is occurring, don't reload any cases in this condition. They will fail.
It is necessary to inspect .303 brass fired in Lee Enfields carefully, and cull as required.
Your primer protrusion isn't as bad as some. That boltface pitting is ugly.
I suspect that your rifle is on the loose side, as many Lee Enfields are. Tightening up the headspace would not be a bad idea.
