25-06AI headspace?

[cbuck516]

I have recently built a 25-06AI on a howa 1500 action using a preferred barrels prefit. I have had amazing results with the rifle so far and am now getting groups near 1/2MOA after doing load development.

However, I am starting to question if I got the headspace set correctly and here is why...

I used PTG go/no-go gauges for "25-06 Remington Ackley Improved 40 Degree Shoulder" to set the headspace on this 25-06AI rifle. This resulted in a headspace of 2.099" on fire-forming and 2.100" on subsequent firings using lapua 30-06 brass and a whidden 0.375" datum.

When I run this fired brass through my full length Redding S die for "25-06 Remington Imp 40degree" the die cams over before it ever touches the shoulder. I have a few remington brass cases that I used to do the intial break in on this barrel and those cases measure 2.102". After running those through my sizing die the shoulder is never bumped. When I try to chamber one of these resized cases it is jammed pretty tight into the chamber and bolt closure is pretty stiff. My lapua case are slowly growing in length and I am sure before long they will also be stiff on bolt closure. My first thought was to simply take some material off the bottom of the sizing die so that I could make sure I am bumping my should back 0.002", but now I am wondering if my headspace is indeed set correctly.

I have some plain jane 25-06 cartridges that I have test chambered in my rifle and they do chamber, but with slight stiffness. Not as stiff as my 2.102" brass, but noticeably stuff. I'm not positive exactly how stiff this should be to be honest and further has me worried that maybe I don't have my headspace set correctly even though I used a set of PTG go/no-go gauges.

For those that are shooting a 25-06AI, what dimension is your headspace set at and what method did you use to set your headspace?

 

[Seabeeken]

I use Manson HS gauges for my Ackleys. They are the only ones that I know of that provide the .004 crush fit that Ackley intended on the factory case. My PTG gauges always seem to do as yours do. Will a factory 25-06 case fit tightly into the chamber? If not, its a bit loose. A 25-06 case should fit snugly into the chamber, making contact at the neck shoulder junction. If it doesnt, it isnt HS properly.

 

[cbuck516]

I use Manson HS gauges for my Ackleys. They are the only ones that I know of that provide the .004 crush fit that Ackley intended. My PTG gauges always seem to do as yours do. Will a factory 25-06 case fit tightly into the chamber? If not, its a bit loose

I will have to grab some factory ammo and see. My 25-06 reloads definitely have slight crush fit in the 25-06 AI chamber, but I would believe that a factory cartridge may not be as tight.

If I add further crush for factory ammo that would mean that I would have to further reduce my headspace which doesn't help my issue with the shoulders not getting bumped.

Do you have a 25-06AI yourself that you could measure headspace on?

 

[Seabeeken]

I will have to grab some factory ammo and see. My 25-06 reloads definitely have slight crush fit in the 25-06 AI chamber, but I would believe that a factory cartridge may not be as tight.

If I add further crush for factory ammo that would mean that I would have to further reduce my headspace which doesn't help my issue with the shoulders not getting bumped.

Do you have a 25-06AI yourself that you could measure headspace on?

I have 5 AI cartridges but no 25-06. Can you check the difference between the headspace as is and headspace when you snug the barrel on a factory round? Some folks use a factory round to set headspace for AI. Id grind own a shellholder before I'd remove material from the die.

 

[cbuck516]

I have 5 AI cartridges but no 25-06. Can you check the difference between the headspace as is and headspace when you snug the barrel on a factory round? Some folks use a factory round to set headspace for AI. Id grind own a shellholder before I'd remove material from the die.

I may try that with a factory round here soon if I can't find anyone with answers. I'm waiting to hear back from PTG right now regarding what headspace they have their gauges designed for.

That is a really good point on the shell holder. I don't set any of my sizing dies to cam over so removing some material from the top of my shell holder shouldn't impact any of my other loads that use that same shell holder.

 

[KNOTFERSAIL]

Here's what I do…."polish the top of the shell holder"

600 grit paper with a drop of water, on a table, take the shell holder holding flat/level a dozen passes back and forth on the paper and measure the depth of the holder.. Doesn't take long to remove a .001 or 2 off the holder. It's a win win now you're not camming over as hard and you brass is going a thou or two deeper in the die bumping the shoulder.

Hopefully this makes sense

 

[MagnumManiac]

If the case is short and the die long, the only true fix is to turn .010" off the top of the shell holder and keep it with that die set.
If standard 25-06 cases chamber ever so tightly, then headspace is correct because Ackley headspace is actually negative by .004"-.005".

Cheers.

 

[blackbrush1]

On a couple of my Ackley cartridges, I have had to remove a small amount of material off the bottom of my resizing dies

 

[Schw15]

I've had ackleys that I needed to grind down a shell holder actually other calibers as well. Sometimes it just works that way. But a factory 25-06 case should close harder on a proper ackley chamber. Sometimes ackleys can cause some headaches depending on how it's setup

 

[Barehandlineman11]

Your die probably is too long and just not reaching it. You can try redding shell holders if that doesn't work then shorten up your die. I've done it in past with belt sander best with lathe. As long as your factory 25-06 chambers your good.

 

[Alibiiv]

I have recently built a 25-06AI on a howa 1500 action using a preferred barrels prefit. I have had amazing results with the rifle so far and am now getting groups near 1/2MOA after doing load development.

However, I am starting to question if I got the headspace set correctly and here is why...

I used PTG go/no-go gauges for "25-06 Remington Ackley Improved 40 Degree Shoulder" to set the headspace on this 25-06AI rifle. This resulted in a headspace of 2.099" on fire-forming and 2.100" on subsequent firings using lapua 30-06 brass and a whidden 0.375" datum.

When I run this fired brass through my full length Redding S die for "25-06 Remington Imp 40degree" the die cams over before it ever touches the shoulder. I have a few remington brass cases that I used to do the intial break in on this barrel and those cases measure 2.102". After running those through my sizing die the shoulder is never bumped. When I try to chamber one of these resized cases it is jammed pretty tight into the chamber and bolt closure is pretty stiff. My lapua case are slowly growing in length and I am sure before long they will also be stiff on bolt closure. My first thought was to simply take some material off the bottom of the sizing die so that I could make sure I am bumping my should back 0.002", but now I am wondering if my headspace is indeed set correctly.

I have some plain jane 25-06 cartridges that I have test chambered in my rifle and they do chamber, but with slight stiffness. Not as stiff as my 2.102" brass, but noticeably stuff. I'm not positive exactly how stiff this should be to be honest and further has me worried that maybe I don't have my headspace set correctly even though I used a set of PTG go/no-go gauges.

For those that are shooting a 25-06AI, what dimension is your headspace set at and what method did you use to set your headspace?View attachment 464192

I am not sure about your headspace issue, however I would like to make a suggestion about adjustment. I suggest that instead of removing material from your die, take the material off of the shell holder instead. If you go too far with the material removal, the shell holder can easily be replaced for $8.00. Just a thought.

 

[Dave in WI]

I am not sure about your headspace issue, however I would like to make a suggestion about adjustment. I suggest that instead of removing material from your die, take the material off of the shell holder instead. If you go too far with the material removal, the shell holder can easily be replaced for $8.00. Just a thought.

I always modify the cheapest part to replace.....

 

[UncleDano]

Since you say that the standard factory 25-06 ammo chamber with slight stiffness, sounds like the headspace is correct.
Must be a slightly long sizing die you have there. See if grinding the shell holder works for you.

 

[VinceMule]

I use Manson HS gauges for my Ackleys. They are the only ones that I know of that provide the .004 crush fit that Ackley intended on the factory case. My PTG gauges always seem to do as yours do. Will a factory 25-06 case fit tightly into the chamber? If not, its a bit loose. A 25-06 case should fit snugly into the chamber, making contact at the neck shoulder junction. If it doesnt, it isnt HS properly.

I like a snug fit, re lube the bolt lugs as needed.

A gunsmith can take a headspace gauge, take .004-.006 off the back of the std GO gauge, call it done.