Gunsmithing Savage with new bolt head.....headspace question

[GLN305]

To preface this question, I had a primer blow out and stick the ejector on my Savage BA Stealth in 6.5CM. The ejector could not be removed at all, so I ordered a new bolt head and replacement parts to populate the bolt head. I measured both bolt heads with calipers to compare lug thickness, face depth and every other measurement I could make with calipers and the new bolt head was within a thousandth in all dimensions, most were spot on the same.

That being said, is it safe to assume that with just replacing the bolt head and measuring both that my headspacing should be OK? I haven't ordered a NoGo gauge yet, but if necessary, I absolutely will.

 

[gnochi]

Back of crosspin to bolt face is the measurement you need, and it’s not trivial to get. It is possible, though. It’s just a better idea to use gauges, especially given how inexpensive they are and how easy it is to have the whole thing blow up in your face.

That said, since this is a Savage, I highly recommend a go gauge or a go/nogo/field set instead; one of the advantages to the Savage platform is the off the shelf barrels.

You can also use a go gauge as a no-go gauge by adding a small piece of paper between the bolt face and the back of the go gauge. That’ll give you about go+0.004”, which is a common no-go length.

Edit: removed faulty measurement info.

 

[GLN305]

I had a feeling that was going to be the case and already ordered a gauge set. I appreciate the advice and want to be as safe as possible know how critical headspace is. I'll report back with my findings after the gauge set arrives. Shipping to AK takes a while LOL

 

[Average guy]

I just went through the same experience. I thoroughly blueprinted both bolt heads and they were basically identical. That being said I also verified with gauges for piece of mind. Just remember to leave the ejector out while using the gauges

 

[MakeSawdust]

Please explain to me why the measurement from cross pin to the bolt face has anything to do with headspace. I am not saying you are wrong, but I am having a very hard time understanding the logic. The bolt head bears on the back of the locking lugs to the lug abutments in the action. Since the barrel has not moved, I would think knowing the distance from the back of the lugs to the bolt face should give him the difference in headspace between the two bolt heads. The distance to the cross-pin will effect primary extraction, but I can't figure out how it will effect headspace. Could someone please explain this to me?

 

[gnochi]

No, I got confused about stack order due to a discussion on T/C break actions. The pin to face measurement would matter with a floating head if the lugs were on the bolt body still. (Pro tip, don’t design a bolt action like that.)

 

[GONE BAD]

Just out of curiosity, how did you pop that primer?
Hand loads or factory ammo?
Also is this rifle new?

I have several savages and I've popped primers, blown ejectors and extractors and it's always been something that was lack of good judgement on my part.

I'd be looking for the cause before just installing a new bolt head.
But you probably already know this?

Anyway I would get the gauges and make sure the headspace is GTG.

Also as mentioned earlier, a new bolt head can lead to problems with primary extraction. Especially if it's a PTG bolt head.

 

[Praeger]

Just out of curiosity, how did you pop that primer?
Hand loads or factory ammo?
Also is this rifle new?

I have several savages and I've popped primers, blown ejectors and extractors and it's always been something that was lack of good judgement on my part.

I'd be looking for the cause before just installing a new bolt head.
But you probably already know this?

Anyway I would get the gauges and make sure the headspace is GTG.

Also as mentioned earlier, a new bolt head can lead to problems with primary extraction. Especially if it's a PTG bolt head.

I had a Savage Model 12 in 223 Remington and after some time began to experienced pierced primers. Hand loads, nothing pushing the edge. Judging from the Savage Shooters Forum, it is not uncommon in Savages and is often caused by excessive firing pin gap at the bolt face. I replaced the bolt head with a PTG, and the issue disappeared.

 

[memilanuk]

I replaced the bolt head with a PTG, and the issue disappeared.

Good to hear that fixed it for you. A better option would have been to send the bolt off to get the firing pin hole bushed, but at the end of the day, if it works, it works

 

[Steel head]

When I switched to a PTG bolt head headspace changed about 9 thousandths longer.
Re set barrel and all was GTG.

 

[Greg Langelius *]

Within the past year, I had a similar outcome. It was with an old Savage (2001 10FP) that had had its .260 barrel replaced with a .30BR barrel. When reconverting back to the .260, I had used my usual field-expedient, a fired case from the same barrel. Although I had historically promoted this method, it finally backfired on me.

I immediately did what I should have originally done and bought the go-gauge.

When combined with electrical tape on the gauge base to fashion a no-go gauge; this adds approximately .005" to the headspace value. At USMC Engineer Electrician School in 1966, that was the thickness value we were taught to use when figuring vinyl electrical tape thickness.

Greg

 

[Praeger]

Good to hear that fixed it for you. A better option would have been to send the bolt off to get the firing pin hole bushed, but at the end of the day, if it works, it works

If it was an AI bolt, absolutely. A factory Savage bolt head is hardly worth it unless no other options. The PTG was head and shoulders above the factory bolt head, half the cost of a bushing job, and the rifle was back in service in a week.

 

[memilanuk]

Eh... I've got more than a few of both (factory and PTG bolt heads). The PTG look nice & crisp, because they don't tumble them after machining... but they aren't all that.

Not as dimensionally consistent as you might think, they don't have the fillet between the stem and the head, and they leave a large amount of the firing pin unsupported, to the point where the tip actually comes free of the smaller diameter hole (similar to on a Remington). On a factory bolt head, the pin tip is fully supported and never comes out of the hole - even when fully cocked. Bushing them only makes them better... and there are at least a couple places that will have them back to you in a week, maybe two at the outside. Pricing varies depending on who you have do it - Gre-tan or Grimstod. The latter is *much* less expensive.

 

[GLN305]

Just out of curiosity, how did you pop that primer?
Hand loads or factory ammo?
Also is this rifle new?

I have several savages and I've popped primers, blown ejectors and extractors and it's always been something that was lack of good judgement on my part.

I'd be looking for the cause before just installing a new bolt head.
But you probably already know this?

Anyway I would get the gauges and make sure the headspace is GTG.

Also as mentioned earlier, a new bolt head can lead to problems with primary extraction. Especially if it's a PTG bolt head.

The ammo was factory 140gr Hornady ELD Match I bought on the way to the range that day. Looking at everything that I can measure with calipers or lesser tools, I couldn't find anything wrong. I brought the rifle home and examined the bolt, took it apart and examined the individual parts and nothing looked out of sorts even when compared to a factory new Savage bolt. The rifle is about a year and a half old and I bought it new and have put around 600 rounds through it before this failure. I was actually going to take it to the AK PRC1 class to see if a Savage could finally make it through the course. At this point, I'm going to investigate further after I get the head space gauge.

Forgot to add that the primer wasn't pierced, it was blown out of the back of the case. I have the brass and plan to seat a primer in it and find out if maybe the primer pockets were not made correctly.

 

[GONE BAD]

The ammo was factory 140gr Hornady ELD Match I bought on the way to the range that day. Looking at everything that I can measure with calipers or lesser tools, I couldn't find anything wrong. I brought the rifle home and examined the bolt, took it apart and examined the individual parts and nothing looked out of sorts even when compared to a factory new Savage bolt. The rifle is about a year and a half old and I bought it new and have put around 600 rounds through it before this failure. I was actually going to take it to the AK PRC1 class to see if a Savage could finally make it through the course. At this point, I'm going to investigate further after I get the head space gauge.

Forgot to add that the primer wasn't pierced, it was blown out of the back of the case. I have the brass and plan to seat a primer in it and find out if maybe the primer pockets were not made correctly.

I really feel you got something going on with the rifle or the ammo.
Huge pressure spike!
I went through this and carbon build up was the culprit.
My rifle had huge skike in pressure and velocity was way low.
I was advised by a really knowledgeable person that carbon ring was probably the problem. Turned out he was absolutely right!
On a side note; carbon buld up is extremely hard to remove. When you think it's gone, it's more than likely NOT.
Just a heads up ?

 

[GLN305]

I really feel you got something going on with the rifle or the ammo.
Huge pressure spike!
I went through this and carbon build up was the culprit.
My rifle had huge skike in pressure and velocity was way low.
I was advised by a really knowledgeable person that carbon ring was probably the problem. Turned out he was absolutely right!
On a side note; carbon buld up is extremely hard to remove. When you think it's gone, it's more than likely NOT.
Just a heads up ?

I'll break out the bore scope this evening, I would love for it to be that simple. I also wonder if the SSS improved ejection parts could have held the case off the bolt face just enough.

 

[memilanuk]

Assuming the headspace was set correctly, there's almost nothing involving the bolt that could be causing the primers to back out.

The Savage ejectors are kind of notorious for going down if they take a hard hit from a hot load. Usually it's the ejector *spring* that fails, and replacing that is pretty simple.

In more recent years, they moved to putting a little 'tail' on the ejector itself, to act as a stop so the ejector plunger couldn't fully collapse the spring and squash it. For the most part, i haven't seen or heard of the ejector spring being a failure point since - but I suppose it's still possible.

Sometimes what gets the ejector plunger stuck in the bolt head is brass flowing into the hole, pushing it back, and getting shaved off when the bolt is opened. That's what causes the 'smear' or 'wipe' marks you see on the case heads. Some of that crap gets into the hole *around* the ejector, and it'll wedge it good. Occasionally it's possible to vibrate it loose using the tip of an engraving tool, but given the cost of a new bolt head it's generally not worth the effort, TBH.

I'd say it's far more likely you had something go wonky with your ammo, or something else. ~600 rds isn't where I'd expect to see a carbon ring forming in a 6.5 CM, unless your cleaning process is seriously sub-standard. Wrong powder, wrong charge weight, wrong bullet slipped in with the rest, all possibilities. Shooting in the rain or with wet ammo will blow the $hit out of primers right freakin' now, as will not using a bore guide and having solvent in the chamber when you pull the trigger.

Any and all of the above is far more likely than the bolt head, especially if it was working fine and then suddenly blew a primer clean out of the case, to the point where it jammed the ejector in the bot face.

 

[GLN305]

Assuming the headspace was set correctly, there's almost nothing involving the bolt that could be causing the primers to back out.

The Savage ejectors are kind of notorious for going down if they take a hard hit from a hot load. Usually it's the ejector *spring* that fails, and replacing that is pretty simple.

In more recent years, they moved to putting a little 'tail' on the ejector itself, to act as a stop so the ejector plunger couldn't fully collapse the spring and squash it. For the most part, i haven't seen or heard of the ejector spring being a failure point since - but I suppose it's still possible.

Sometimes what gets the ejector plunger stuck in the bolt head is brass flowing into the hole, pushing it back, and getting shaved off when the bolt is opened. That's what causes the 'smear' or 'wipe' marks you see on the case heads. Some of that crap gets into the hole *around* the ejector, and it'll wedge it good. Occasionally it's possible to vibrate it loose using the tip of an engraving tool, but given the cost of a new bolt head it's generally not worth the effort, TBH.

I'd say it's far more likely you had something go wonky with your ammo, or something else. ~600 rds isn't where I'd expect to see a carbon ring forming in a 6.5 CM, unless your cleaning process is seriously sub-standard. Wrong powder, wrong charge weight, wrong bullet slipped in with the rest, all possibilities. Shooting in the rain or with wet ammo will blow the $hit out of primers right freakin' now, as will not using a bore guide and having solvent in the chamber when you pull the trigger.

Any and all of the above is far more likely than the bolt head, especially if it was working fine and then suddenly blew a primer clean out of the case, to the point where it jammed the ejector in the bot face.

I completely agree. I simply expect a bad lot of ammo to be the root cause.

 

[GLN305]

Headspace gauges came in, bolt would close with extra effort on the Go gauge and wouldn't even start to close on the No Go. I chambered a round and it felt great, so I assume the headspace is good?

 

[memilanuk]

With a stripped bolt (no ejector, no primary extraction cam, no cocking sleeve, no wave washer. Keep the firing pin assy. to hold the toggle pin in place) it should drop freely on the GO gauge, and not at all on the NO-GO gauge. Hook the rim of the gauge under the extractor so you don't have to push over it, interfering with the feel.

And when I say 'drop freely' I mean just that; the handle should drop closed under its own weight, with no 'extra effort'.

 

[GLN305]

With a stripped bolt (no ejector, no primary extraction cam, no cocking sleeve, no wave washer. Keep the firing pin assy. to hold the toggle pin in place) it should drop freely on the GO gauge, and not at all on the NO-GO gauge. Hook the rim of the gauge under the extractor so you don't have to push over it, interfering with the feel.

And when I say 'drop freely' I mean just that; the handle should drop closed under its own weight, with no 'extra effort'.

Went and stripped the bolt, tried the Go gauge again and it will not close freely under its' own weight, it would require some force to close it. No Go gauge doesn't allow the bolt handle to move at all. I assume the headspacing is too tight and I need to re-headspace.

 

[memilanuk]

That'd be my call as well.

 

[GLN305]

That'd be my call as well.

I really appreciate your help! I am going to order a savage barrel nut wrench right now and make some barrel vise blocks to make it happen. I'll report back when the wrench gets here.

 

[gnochi]

I really appreciate your help! I am going to order a savage barrel nut wrench right now and make some barrel vise blocks to make it happen. I'll report back when the wrench gets here.

If you have the smooth barrel nut, I advise getting a square-groove replacement nut and the 11in barrel nut wrench from Northland Shooters Supply. Being careful with a hacksaw or dremel, you can cut a shallow groove 1/8in in front of the action in the smooth nut, then remove it with vise grips or channel locks. This of course means the nut can’t be reused.

You will also want an action wrench and a vise if you don’t have one; the barrel nuts are installed by gorillas, and I advise holding the barrel, action, and recoil lug when you’re torquing the new nut or removing the old one.

Also, get some Permatex Nickel anti-seize from an auto parts store and lightly lubricate the barrel threads before you thread on the nut and reinstall the barrel (you need to entirely remove the barrel to replace nuts).

 

[GLN305]

If you have the smooth barrel nut, I advise getting a square-groove replacement nut and the 11in barrel nut wrench from Northland Shooters Supply. Being careful with a hacksaw or dremel, you can cut a shallow groove 1/8in in front of the action in the smooth nut, then remove it with vise grips or channel locks. This of course means the nut can’t be reused.

You will also want an action wrench and a vise if you don’t have one; the barrel nuts are installed by gorillas, and I advise holding the barrel, action, and recoil lug when you’re torquing the new nut or removing the old one.

Also, get some Permatex Nickel anti-seize from an auto parts store and lightly lubricate the barrel threads before you thread on the nut and reinstall the barrel (you need to entirely remove the barrel to replace nuts).

Mine already has the square groove barrel nut, so I'm good there. I ordered the Wheeler wrench, but I will also order the NSS wrench because two is one and one is none. I'll also order an action wrench and vise, might as well have the tools. Once again, thank you!

 

[GLN305]

All my tools arrived and I set the head space according to everything I have read everywhere. With a stripped bolt, the go gauge allows the bolt to drop closed with zero effort. With the NoGo gauge, the bolt handle moves a small amount and comes to a dead stop at about 1/8 of the total travel distance far before the bolt closes. After doing this, my assumption is the head space was set tight from the factory. I am also recalling that, with the rifle straight out of the box, that factory Hornady would chamber and fire, but my hand loads with Lapua brass full length re-sized with Redding dies would cause a similar bolt tightness that I found after the bolt head replacement.