Bolt Head Interchange

I apologize if this is a repeat question but I could not find any threads about it. I want to make some very accurate measurements of bullet ogive to the lands. The best way to do this is by removing the firing pin, ejector, and extractor from the bolt to allow for the best “feel” of when the bullet touches the lands. I am a bit leery of knocking out that tiny pin holding the ejector on a regular basis so I have an alternate plan. Just use a stripped bolt head in place of my normal one. My question (you knew I’d get to it eventually) is this: are Savage bolt heads dimensionally consistent enough for this to work? I realize that the spring tension of the floating bolt head my make the whole thing moot but I want to see if it will work.

The critical dimensions of the two bol theads would need to be identical. The one being used in the firearm and the one you use to test with.

You could remove the BAS and use the firing pin to old the cross-pin in place and then use the bolt close method. Works for me every time. There are several ways to skin this cat.

I learned this method watching a u-tube video. Of coarse it was on a Rem or clone style action. The PE cam caused a small audible "click" as the bullet pulled free of the lands. They kept shortening the dummy round until no "click" was present. These actions had nothing interfering with the bolt so it could actually free fall.
In order to accomplish this on a Savage you must remove the ejector, remove the cocking pin and cocking sleeve from the bolt. Also the wave washer. Reinstall the firing pin to hold the crosspin. But the real "pita" is the removal of the detent balls & spring in the rear baffle.
The bolt will then be in "free fall". The rear baffle will be flopping around, secure it lightly to the action with a small piece of tape. (I have a spare "stripped" rear baffle for this use).
You do need the extractor in place for this method. I believe it is called the "Wheeler" method. It works well and you will feel the slightest "click" when the PE removes the bullet from the lands.
Also I agree with Robin the bolt heads would have to be perfect. After you remove the ejector a few times it will become second nature and is no big deal.
Search for the u-tube video you will be amazed.

Using my split case method for many years, and found it was a waste of
time to remove anything.....On extraction, I hold my hand over the port.
Once the case head has released, I just tilt the rifle and let the dummy
roll onto my hand. I don't over think it. My plus or minus tolerance is +.001
-.001

If I understand your objective correctly, why not just use one of these and the comparator set? https://uploads.tapatalk-cdn.com/202...123dc0fb71.jpg

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"Using my split case method for many years, and found it was a waste of time to remove anything" :cool::cool:

Think about it. All the extractor does is snap over the case rim and hold it against the bolt head.
When you slide the bolt into the action body, it's COCKED and the firing pin doesn't stick out beyond the bolt head surface. Wasted efforts. What it comes down to is "what ever makes you feel good".
Out of maybe 10/12+ barrel swaps, never removed anything from the bolt head. And if the ejector has enough strength to push the case sideways in the chamber, you've got more problems than a too strong ejector spring. :eek:
I always a Hornady tool with a modified case to set the OAL and find the lands on my ammo. Got cases for each caliber I shoot.
Did run into a situation a while back that gave me pause. Sent a couple cases off to Hornady to have modified. Got them back and the bullet wouldn't slide in the neck??? We always do them that way??? Except for ALL the cases they had previously modified for me. :rolleyes::rolleyes:
Had a go round with the folks about that so just maybe a "split neck" case may be the better way to go, depending on availability. YMMV.

For those of you that use the Hornady set up, Have you ever checked the case headspace and compared it to your sized case? When I found one at .010 shorter I started making my own.

Something else I've consistently found, even in bergers, smk, eld, every pill I've bought, when you measure the base of the pill to the ogive, i have had as much as .003 variation in the same lot of pills so I started measuring and sorting the pills themselves to get my loads as close as possible. I only do this on ammo I'm loading for competition

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Quote:

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Originally Posted by Robinhood

For those of you that use the Hornady set up, Have you ever checked the case headspace and compared it to your sized case? When I found one at .010 shorter I started making my own.

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Not sure i follow ya.. would that matter if your just getting the jump space measurement?

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Quote:

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Originally Posted by Ted_Feasel

Not sure i follow ya.. would that matter if your just getting the jump space measurement?

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When you measure your loaded ammo length you measure from the base of the case to the ogive...at least I did. ( I guess if you measured from the shoulder to the ogive you would be ok, I have not seen a tool for that) If the modified case is .010" shorter than you case, your jump will be .010" different. You are not using a case that is within a few thousands of your bolt face you could be using a case that is .010" off of your bolt face or longer. This is the reason I don't use this method anymore.

Quote:

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Originally Posted by Robinhood

When you measure your loaded ammo length you measure from the base of the case to the ogive...at least I did. ( I guess if you measured from the shoulder to the ogive you would be ok, I have not seen a tool for that) If the modified case is .010" shorter than you case, your jump will be .010" different. You are not using a case that is within a few thousands of your bolt face you could be using a case that is .010" off of your bolt face or longer. This is the reason I don't use this method anymore.

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Isn't base to ogive what your after? Its just a relative measurement to get the distance, for example on one of my match 308s , using hornady 178gr ELD I can push it out to 2.886 OAL for ogive to touch. That distance from the base to ogive touching is a constant isnt it or am I still not understanding you?

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It would be nice to know what dimension you measure once you used your method for finding the lands. This way I could explain things more clearly.

I'll try this, Do you push the modified case to the shoulder then push the bullet to the the ogive to get your measurement? Do you then measure your base of the case to the ogive for your BTO length?

Quote:

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Originally Posted by Robinhood

It would be nice to know what dimension you measure once you used your method for finding the lands. This way I could explain things more clearly.

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What I do is place the modified case with a bullet in it, making sure I'm keeping the modified case seated in the chamber i push the bullet out until it stops, tighten the thumb screw to lock it in place then with bullet comparator bushing and calipers I measure from base to ogive and get my baseline. Then when I load my resized case I usually start lets say since my 308 shilen gives me a oal of 2.886 max, I start with seating at 2.866 and work out until I see pressure issues and groups doing what I want, once I find the magic spot for a particular type of pill, I take the bullet comparator bushing and measure that load from base to ogive and seat my pills to that depth.

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Have you measured the Base to Shoulder of your modified case and compared that length to a fired case?

Quote:

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Originally Posted by Robinhood

Have you measured the Base to Shoulder of your modified case and compared that length to a fired case?

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No because the base of the modified or resized case stop the case shoulders from touching. When I resize for my bolt, I neck size and shoulder bump only to .002 headspace relief

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If you don't recognize that the length of the case base to shoulder dimension on your modified case is critical in your measurements, then it is all mute.

Another thing nice about the split case method is actually seeing where the
boat tail starts in relation to the donut region after the push is made. Gives
a good idea for ya' if you decide to try deeper and jump em'. I picked up
some .264 144gr Bergers to test in a 7.5 twister. For the hell of it, I pushed
them to touch the lands in my 8 twister. The beginning of the boat tail was
only half way down the neck !! Super Extra Slender !! LOL

No matter the method, and what's been mentioned in several posts, it all
really boils down to your bullet sort. I sorted some of the new Berger .264
144 grainers. Just a box of 100 gave me 5 piles sorted with my Harrrels.
I really expected better ??

Quote:

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Originally Posted by Robinhood

If you don't recognize that the length of the case base to shoulder dimension on your modified case is critical in your measurements, then it is all mute.

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How is what I'm asking? In the context of finding base to ogive, shoulders play no part unless the were pushed out to far to where the were affecting how far out the base of your case is out

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Quote:

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Originally Posted by Robinhood

If you don't recognize that the length of the case base to shoulder dimension on your modified case is critical in your measurements, then it is all mute.

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Are you referring to this part of the shoulder or head space being .01 off?https://uploads.tapatalk-cdn.com/202...863c9a91a5.jpg

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Agreeing with Fuj, the split case method works great I used a variation of that for years. I drilled and tapped the case head of standard primer cases to 1/4-20 and small rifle cases to 12-24. Then set the neck tension to just under a thousandth. The tapped holes were used to push the bullet back out after forcing them in. A Sharpie mark was added when seating depth was close to touching.
Once first contact is made CBTO can be measured for that rifles baseline.

My current method uses a brass rod measurement from muzzle to bolt face and then from bullet tip to muzzle. The bullet can then be set in a dummy to verify the difference with a Sharpie mark. CBTO measurement off that dummy is also almost a "perfect" baseline.

Many ways to skin this cat. And all are only related to the action/barrel they were taken from.

Quote:

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Originally Posted by Ted_Feasel

Are you referring to this part of the shoulder or head space being .01 off?https://uploads.tapatalk-cdn.com/202...863c9a91a5.jpg

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Because that may be wear im not getting what your saying. If your saying that edge of the shoulder then I can understand that make a difference but if your referring to head space of the modified case then I can't see it making a difference

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Thinking outloud, the modified case should have the same headspace as the bump you set in your handloads or the CBTO will be different between the two.
The baseline however is what we all work with and should be consistent. The baseline is where we work from incrementally. It doesn't make a difference where we physically end up because best results will be unique to that rifle only.

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Originally Posted by mnbogboy2

Thinking outloud, the modified case should have the same headspace as the bump you set in your handloads or the CBTO will be different between the two.
The baseline however is what we all work with and should be consistent. The baseline is where we work from incrementally. It doesn't make a difference where we physically end up because best results will be unique to that rifle only.

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I agree. The comparator is not dealing in absolutes as much as it is giving a reference point or baseline that is worked up from.

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Ted, Sorry for the gap in time, I had to take an old man nap. My point hinges on a gauge that is significantly longer or shorter than the length gauged of ones rifle chamber. That is why I asked if anyone had ever measured the case headspace on there modified cases. Some may be close to your headspace. Many of mine were off.

When you have found your lands with the hornady tool, you take you measurement from the base of the of the modified case to the ogive(CBTO). Then you you will load based on that information. If you cases that you are loading are a different dimension from the base to the shoulder then the point where the bullet touches the lands will be an unknown. Granted, that may not matter if you start with a .030 jump.

Some people start with the bullets touching the lands and work away once they have found the load. If you notice that some guys are worried about any little interference that may impact their measuring. I'm not quite that anal. If you push something into the lands it will scar the bullet. Possibly even stick the bullet when you extract.



I believe the split neck gauge is an improvement over the hornady setup for the reason that if you are using a case that fits that chamber, you are getting a very precise measurement. I use a dummy round and us the bolt close method. I retain the dummy round for reference I can re run the test after x number of rounds and see if my lands are moving. That oddball BTO bulet comes in handy here.

Good banter and thanks for humoring me.

Quote:

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Originally Posted by Robinhood

Ted, Sorry for the gap in time, I had to take an old man nap. My point hinges on a gauge that is significantly longer or shorter than the length gauged of ones rifle chamber. That is why I asked if anyone had ever measured the case headspace on there modified cases. Some may be close to your headspace. Many of mine were off.

When you have found your lands with the hornady tool, you take you measurement from the base of the of the modified case to the ogive. Then you you will load based on that information. If you cases that you are loading are a different dimension from the base to the shoulder then the point where the bullet touches the lands will be an unknown. Granted, that may not matter if you start with a .030 jump.

Some people start with the bullets touching the lands and work away once they have found the load. If you notice that some guys are worried about any little interference that may impact their measuring. I'm not quite that anal. If you push something into the lands it will scar the bullet. possibly even stick the bullt when you extract.



I believe the split neck gauge is an improvement over the hornady setup for the reason that if you are using a case that fits that chamber, you are getting a very precise measurement. I use a dummy round and us the bolt close method. I retain the dummy round for reference I can re run the test after x number of rounds and see if my land are moving. That oddball BTO bulet comes in handy here.

Good banter and thank for humoring me.

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I definitely start far and work closer, I recon thats why it never played a hand in my load dev and jump dev. BTW, I cleaned the garage and took a nap also:)

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I drank a Molsen XXX and watched a retro world series between
the Twinns And Atlanta. Some where in between the third and
eighth innings I caught my nap.

Last couple of years has found me to start at .015 off the lands.
Seems to have saved me in resources overall.

Good thread !!

I'm glad I'm not the only one.
Gunracr, sorry for hijacking. Did you get the info you wanted?

nobody has mentioned the wheeler method as of yet. also very effective. check out their website Wheeler engineering

If this is the video, that is what I was talking about by setting it on bolt close. I find that to be exact as in within .001"

https://www.youtube.com/watch?v=TWmIwPwLyyg

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Originally Posted by strut64

nobody has mentioned the wheeler method as of yet. also very effective. check out their website Wheeler engineering

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I mentioned this in post #3 with all the modifications to the savage bolt.
Thanks Robin, that's the video I mentioned too. Yes, super accirate. The "human" feel of the bullet seating gets a realistic assist from the PE.

Quote:

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Originally Posted by mnbogboy2

I learned this method watching a u-tube video. Of coarse it was on a Rem or clone style action. The PE cam caused a small audible "click" as the bullet pulled free of the lands. They kept shortening the dummy round until no "click" was present. These actions had nothing interfering with the bolt so it could actually free fall.
In order to accomplish this on a Savage you must remove the ejector, remove the cocking pin and cocking sleeve from the bolt. Also the wave washer. Reinstall the firing pin to hold the crosspin. But the real "pita" is the removal of the detent balls & spring in the rear baffle.
The bolt will then be in "free fall". The rear baffle will be flopping around, secure it lightly to the action with a small piece of tape. (I have a spare "stripped" rear baffle for this use).
You do need the extractor in place for this method. I believe it is called the "Wheeler" method. It works well and you will feel the slightest "click" when the PE removes the bullet from the lands.
Also I agree with Robin the bolt heads would have to be perfect. After you remove the ejector a few times it will become second nature and is no big deal.
Search for the u-tube video you will be amazed.

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:tea:

Quote:

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Originally Posted by Fuj'

Using my split case method for many years, and found it was a waste of
time to remove anything.....On extraction, I hold my hand over the port.
Once the case head has released, I just tilt the rifle and let the dummy
roll onto my hand. I don't over think it. My plus or minus tolerance is +.001
-.001

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:thumb: Been doing it that way for years when I don't happen to have the modified case.

Quote:

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Originally Posted by Robinhood

If this is the video, that is what I was talking about by setting it on bolt close. I find that to be exact as in within .001"

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Thanks for posting this. I have been using the Hornady tool and it works ok but is not always repeatable. I learned a lot reading this thread.

I watched that video and I remember my dad and uncle doing something real similar to that when I was a kid just learning

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Quote:

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Originally Posted by Bill2905

Thanks for posting this. I have been using the Hornady tool and it works ok but is not always repeatable.

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A lot of methods and tools available to get it done. As most have found on here,
"repeat ability" is not absolute. Some of these new fangled slender pencils we have
been enjoying for longer ranges, can be a pain in the ass. There are times that you
have to do multiple pushes and settle on the best dispersion. My latest headache
was with the 6.5 150gr Sierras. Those things are real slender and wanted to stick
more then most, which brings up another piece of the puzzle. There are some
machined angles at the start of the lands that are more abrupt then others. These
are easier to feel, whereas an angle that is close to perfect, can be troublesome
If tension is too great in your test case.

Just throw this out there.. sometime when you have a box of pills.. measure from the base of the pill to the ogive..sierra, hornady and bergers I have always found as much as .003 variation .. belive it or not the best I've found is the new hornady Atips.. i guess my point is the inconsistency in where the ogive is can add to the difference in readings... not saying it is the only factor but definitely plays a part.

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Quote:

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Originally Posted by Ted_Feasel

Just throw this out there.. sometime when you have a box of pills.. measure from the base of the pill to the ogive..sierra, hornady and bergers I have always found as much as .003 variation .. belive it or not the best I've found is the new hornady Atips.. i guess my point is the inconsistency in where the ogive is can add to the difference in readings... not saying it is the only factor but definitely plays a part.

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Right you are, and why I use a Holland comparator for my anal stuff. I've also
read that the A-tips have been consistent and probably from the fact that the
lot batches are directly packaged as they come off the press. Buddy tells me
that they ship a cloth to wipe the oil off as you receive them !!

Holland comparator.....Not real cheap, but a good tool.

Quote:

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Originally Posted by Fuj'

Right you are, and why I use a Holland comparator for my anal stuff. I've also
read that the A-tips have been consistent and probably from the fact that the
lot batches are directly packaged as they come off the press. Buddy tells me
that they ship a cloth to wipe the oil off as you receive them !!

Holland comparator.....Not real cheap, but a good tool.

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Yes sir, I dont have the Holland, ive found what the chambers are on my rifles, at least within the variation you may get but because I start with the deepest or default and work my way out until I find what I'm looking for.. i guess it would be neat to know the precise distance.
I have 2 boxes of the atips but have not had the time to do load dev with them. They are very nice, you can tell a great deal of pride and craftsmanship went into the atip.. i love that they are sequinchely packaged into their own slot. I picked out 10 just to see how consistent they are and the 10 i measured were all identical as far as my 49 year old eyes could see on dial cals.. they are mitutoyo my daddy passed down. Very accurate.

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Quote:

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Originally Posted by Robinhood

If you don't recognize that the length of the case base to shoulder dimension on your modified case is critical in your measurements, then it is all mute.

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I would think that would make it all Moot. But I guess anything’s possible in the new Covid-pandemic world of death! LOL! I promise I am simply joking Robin. :becky:


Boy oh boy...You guys are WAY more “precisionalistical-icious” than I with your technique. I do use a Hornady Lock n Load Comparator, but I measured OAL with an Frankford Arsenal OAL kit. The brain fluid aroma is palpable in here!

Thank you for sharing guys. Quite an interesting discussion.

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Originally Posted by Dave Hoback

Boy oh boy...You guys are WAY more “precisionalistical-icious” than I with your technique. I do use a Hornady Lock n Load Comparator, but I measured OAL with an Frankford Arsenal OAL kit. The brain fluid aroma is palpable in here!

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LOL....Yeah. I was'nt alway's this way. As my wild catting came back
into focus as one of my primary rifle hobby's, it went from tipping over
wood chucks to ruining good paper, way out there. And if a chuck is
way out there ?? It's toast.....:cool:

Quote:

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Originally Posted by Fuj'

LOL....Yeah. I was'nt alway's this way. As my wild catting came back
into focus as one of my primary rifle hobby's, it went from tipping over
wood chucks to ruining good paper, way out there. And if a chuck is
way out there ?? It's toast.....:cool:

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^^this^^ no disagreement from this old guy!

Quote:

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Originally Posted by Fuj'

LOL....Yeah. I was'nt alway's this way. As my wild catting came back
into focus as one of my primary rifle hobby's, it went from tipping over
wood chucks to ruining good paper, way out there. And if a chuck is
way out there ?? It's toast.....:cool:

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I hear ya. Hey... I dig it! Quite humbling.

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Originally Posted by mnbogboy2

^^this^^ no disagreement from this old guy!

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I still read about some of your adventures....LOL I got one coming your way that's been on the back burner for 30 years or more !!

And while on the wild catting subject, I'll add another problem we can create for
ourselves to hurt that repeatable measurement. I was reminded of this yesterday
when I stuck a case in a FL die.....If you stick a case, check that you did not deform
any of the case rim. This will skew your numbers, and probably give you problems
on bolt closure. Save these for foulers to get them ironed out.

As for the stuck case ?? Imperial sizing wax failed me again !! Finished the lot with
lanolin.

Quote:

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Originally Posted by Fuj'

I still read about some of your adventures....LOL I got one coming your way that's been on the back burner for 30 years or more !!

And while on the wild catting subject, I'll add another problem we can create for
ourselves to hurt that repeatable measurement. I was reminded of this yesterday
when I stuck a case in a FL die.....If you stick a case, check that you did not deform
any of the case rim. This will skew your numbers, and probably give you problems
on bolt closure. Save these for foulers to get them ironed out.

As for the stuck case ?? Imperial sizing wax failed me again !! Finished the lot with
lanolin.

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Fuj, great info on the distorted rims. I pulled a bunch of old rounds apart a couple of times with the inertia "hammer". Even after breaking "cold welds" in the press by seating them a little deeper the case rims changed. Some actually were visible and unusable. Several thousandths long can easily push you out of a seating node. Or worse yet mixed with regular length cases cause your hair to fallout or turn grey!
It's all learn as we go I guess.