Headspace of Wylde vs. Standard .223

[Religious Shooter]

I set the sizer/trim die on my Dillon to the Dillon .223 mic. The case head falls right between the max and min of the Dillon .223 mic.

I take the same case and drop it into a JP Mic (which I'm assuming is a Wylde --- since it is supposedly cut from the chamber reamer that they use for their barrels) and the case falls below the minimum line.

Either 1) the Wylde and regular .223 chambers have different headspacing or 3) one of the Mics is off or maybe even worn.

Which is it?

I am asking because I'm having case separations with a rifle that has a Wylde chamber. The cases' headspace was set with the Dilon mic.

[Dan Sierpina]

The headspace dimension is the same for both chambers. You have a chamber that is cut to the maximum, and brass that's sized to the minimum.

The Wylde chamber has a modified Nato throat, it's not so sloppy as the Nato version. It was designed to improve accuracy, while keeping pressures lower.

[Tom D.]

Religious shooter,

Take a fired case (actually, repeat on several cases) and size to a .004 shoulder set back keeping in mind that, as you mentioned, your two chambers are different. I use the RCBS case mike to determine this measurement.

[Powder Finger]

I set the sizer/trim die on my Dillon to the Dillon .223 mic. The case head falls right between the max and min of the Dillon .223 mic.

I take the same case and drop it into a JP Mic (which I'm assuming is a Wylde --- since it is supposedly cut from the chamber reamer that they use for their barrels) and the case falls below the minimum line.

Either 1) the Wylde and regular .223 chambers have different headspacing or 3) one of the Mics is off or maybe even worn.

Which is it?

I am asking because I'm having case separations with a rifle that has a Wylde chamber. The cases' headspace was set with the Dilon mic.

The gage is hust that a gage might be different from even from the same company.

If you fire some fairly stout loads with known brass (new,once fired). Keep these for reference.

Take a punch or out of the die decap stem and knock out the primers. Now you can measure the headspace of YOUR chamber with a headspace tool.

Get an average of say 5 cases you are going to keep as your gages. The measurement will be from the back of the case to the datum line on the shoulder

plus the gage measurement. (this will be about .001 short of your actual chamber as the brass bounces back some).

Now take some of the same batch of cases and set up your sizing die to size the cases .004 shorter than that(as mentioned).

You are now good to go.

Also remember the different chamber reamer types don't reflect true headspace the depth the reamer is run in does.

So you could have a Wylde chamber with too much, too little, or between min/max, depending on who did the work. (same as the gages discussed)

Personally I would hesitate trusting a gage until I proofed it to my chamber using the above process.

[Powder Finger]

Just re-read the whole post, the separations are more that likely from sizing the case too much (excess headspace).

The above process will correct that. But you may not be able to use one die setting to feed both rifles.

You will need to get good baseline numbers off of both.

http://ar15barrels.com/tech.shtml

This comares the different reamers and you will notice there is no headspace dimension on any of them, which angain is set by the gunsmith hopefully using SAMMY MIN/MAX specs.?

Edited November 17, 2010 by Powder Finger

[mpeltier]

Have you checked the headspace of that bbl/bolt combo that is experiancing seperation issues? Also what is the velocity those rounds are at and what gas system on the gun. I would be inclined to believe there is possibly something else besides resizing at play here.

[Powder Finger]

The fired case (not separated) using the actual case measurement described earlier can determine a chamber headspace problem which is a probability. Your chamber will be about .001 longer than the case measurement

SAAMI .223 min headspace is 1.4636 max is 1.4736 spec is 1.4666. So you can tell if too much chamber headspace is causing possibly the problem.

http://saami.org/specifications_and_information/publications/download/206.pdf

Edited November 19, 2010 by Powder Finger

[Religious Shooter]

I just got the RCBS mic. I don't have any fired rounds that I know came from this upper's chamber. It's going to be awhile before I can go to the range.

I measured the reloaded "problem" rounds with the RCBS mic and they were -.007 from zero hash on the RCBS mic. I measured some factory rounds and got some averages: Q3131A => 0; Wolf 62 => -.004; Black Hills blue box => -.002.

The reloads are book max load 55's using range brass. The upper was using a lightened bolt-carrier when the seprations occured. It's a mid gas barrel. No adjustable gas block.

I'm going to go with a full weight bolt-carrier to see if it fixes the problem with this batch of ammo.

I think it is was just a "perfect storm" with this upper and load. The lightened bolt... the slightly overbumped shoulders on the brass... range brass... the fact that it's a mid gas barrel... non-adjustable gas... ===> intermittent case separation.

[jaredr]

I set the sizer/trim die on my Dillon to the Dillon .223 mic. The case head falls right between the max and min of the Dillon .223 mic.

I take the same case and drop it into a JP Mic (which I'm assuming is a Wylde --- since it is supposedly cut from the chamber reamer that they use for their barrels) and the case falls below the minimum line.

Either 1) the Wylde and regular .223 chambers have different headspacing or 3) one of the Mics is off or maybe even worn.

Which is it?

I am asking because I'm having case separations with a rifle that has a Wylde chamber. The cases' headspace was set with the Dilon mic.

The gage is hust that a gage might be different from even from the same company.

If you fire some fairly stout loads with known brass (new,once fired). Keep these for reference.

Take a punch or out of the die decap stem and knock out the primers. Now you can measure the headspace of YOUR chamber with a headspace tool.

Get an average of say 5 cases you are going to keep as your gages. The measurement will be from the back of the case to the datum line on the shoulder

plus the gage measurement. (this will be about .001 short of your actual chamber as the brass bounces back some).

Now take some of the same batch of cases and set up your sizing die to size the cases .004 shorter than that(as mentioned).

You are now good to go.

Also remember the different chamber reamer types don't reflect true headspace the depth the reamer is run in does.

So you could have a Wylde chamber with too much, too little, or between min/max, depending on who did the work. (same as the gages discussed)

Personally I would hesitate trusting a gage until I proofed it to my chamber using the above process.

Powder Finger - wondering why you specify removing spent primers before measuring with a headspace tool? Is it because the spent primer may have "dished" or flowed a bit and would throw off the gauge (because flowed primer would exend beyond base of case a thousandth or two)?

[mpeltier]

I just got the RCBS mic. I don't have any fired rounds that I know came from this upper's chamber. It's going to be awhile before I can go to the range.

I measured the reloaded "problem" rounds with the RCBS mic and they were -.007 from zero hash on the RCBS mic. I measured some factory rounds and got some averages: Q3131A => 0; Wolf 62 => -.004; Black Hills blue box => -.002.

The reloads are book max load 55's using range brass. The upper was using a lightened bolt-carrier when the seprations occured. It's a mid gas barrel. No adjustable gas block.

I'm going to go with a full weight bolt-carrier to see if it fixes the problem with this batch of ammo.

I think it is was just a "perfect storm" with this upper and load. The lightened bolt... the slightly overbumped shoulders on the brass... range brass... the fact that it's a mid gas barrel... non-adjustable gas... ===> intermittent case separation.

Have you chrono'd those loads? I would be most suspect of the book max and a non adj gas block with the light BC as the problem. I have ripped rims off with the same set-up (but not at book max on the realods). By adj the gas block, problem went away.

[Religious Shooter]

I doubt that it's the loading. Book max loads are lawyerfied loads. They are almost always way within what the actual max is for a give rifle.

I used the same loading with Scharch brass and they functioned fine at the Nationals. No separations with the 1X fired Scharch brass. The Scharch brass measures -.002 on the RCBS mic.

This batch of reloads uses the same powder charge but with picked up range brass thats headspaced -.007 on the RCBS mic.

Only difference is the overly bumped shoulder and the mixed range brass.

I think if I use the reloads with my rifle length gas gun they would work fine. My mid-gas upper is throwing the brass about 12+ feet. My other uppers with a 20" gas kicks the brass at about 6'+ away. The extraction force with the mid-gas upper is way higher.

[Powder Finger]

I set the sizer/trim die on my Dillon to the Dillon .223 mic. The case head falls right between the max and min of the Dillon .223 mic.

I take the same case and drop it into a JP Mic (which I'm assuming is a Wylde --- since it is supposedly cut from the chamber reamer that they use for their barrels) and the case falls below the minimum line.

Either 1) the Wylde and regular .223 chambers have different headspacing or 3) one of the Mics is off or maybe even worn.

Which is it?

I am asking because I'm having case separations with a rifle that has a Wylde chamber. The cases' headspace was set with the Dilon mic.

The gage is hust that a gage might be different from even from the same company.

If you fire some fairly stout loads with known brass (new,once fired). Keep these for reference.

Take a punch or out of the die decap stem and knock out the primers. Now you can measure the headspace of YOUR chamber with a headspace tool.

Get an average of say 5 cases you are going to keep as your gages. The measurement will be from the back of the case to the datum line on the shoulder

plus the gage measurement. (this will be about .001 short of your actual chamber as the brass bounces back some).

Now take some of the same batch of cases and set up your sizing die to size the cases .004 shorter than that(as mentioned).

You are now good to go.

Also remember the different chamber reamer types don't reflect true headspace the depth the reamer is run in does.

So you could have a Wylde chamber with too much, too little, or between min/max, depending on who did the work. (same as the gages discussed)

Personally I would hesitate trusting a gage until I proofed it to my chamber using the above process.

Powder Finger - wondering why you specify removing spent primers before measuring with a headspace tool? Is it because the spent primer may have "dished" or flowed a bit and would throw off the gauge (because flowed primer would exend beyond base of case a thousandth or two)?

Exactly, you don't want any chance of measuring part of the primer just the back of the case (which is the bolt face).

Also sometimes especially if it's not a stout load the primer will acually back out a little and since we are dealing with thousands

of an inch measurments you want to get as deal on as you can. If you think about it if you have .004 primer set back as part of your measurement

and set your die up to that, then your brass will be .004 long at least. at worst with an AR you are finishing the case sizing in the chamber with

the bolt being the press. In that case you are putting a beating on the bolt and may gall the back of the bolt and barrel extension.

At best you may have function problems.

With a Bolt gun you will probably have a hard to close bolt, but the same damage can occur.

Later

[jaredr]

I set the sizer/trim die on my Dillon to the Dillon .223 mic. The case head falls right between the max and min of the Dillon .223 mic.

I take the same case and drop it into a JP Mic (which I'm assuming is a Wylde --- since it is supposedly cut from the chamber reamer that they use for their barrels) and the case falls below the minimum line.

Either 1) the Wylde and regular .223 chambers have different headspacing or 3) one of the Mics is off or maybe even worn.

Which is it?

I am asking because I'm having case separations with a rifle that has a Wylde chamber. The cases' headspace was set with the Dilon mic.

The gage is hust that a gage might be different from even from the same company.

If you fire some fairly stout loads with known brass (new,once fired). Keep these for reference.

Take a punch or out of the die decap stem and knock out the primers. Now you can measure the headspace of YOUR chamber with a headspace tool.

Get an average of say 5 cases you are going to keep as your gages. The measurement will be from the back of the case to the datum line on the shoulder

plus the gage measurement. (this will be about .001 short of your actual chamber as the brass bounces back some).

Now take some of the same batch of cases and set up your sizing die to size the cases .004 shorter than that(as mentioned).

You are now good to go.

Also remember the different chamber reamer types don't reflect true headspace the depth the reamer is run in does.

So you could have a Wylde chamber with too much, too little, or between min/max, depending on who did the work. (same as the gages discussed)

Personally I would hesitate trusting a gage until I proofed it to my chamber using the above process.

Powder Finger - wondering why you specify removing spent primers before measuring with a headspace tool? Is it because the spent primer may have "dished" or flowed a bit and would throw off the gauge (because flowed primer would exend beyond base of case a thousandth or two)?

Exactly, you don't want any chance of measuring part of the primer just the back of the case (which is the bolt face).

Also sometimes especially if it's not a stout load the primer will acually back out a little and since we are dealing with thousands

of an inch measurments you want to get as deal on as you can. If you think about it if you have .004 primer set back as part of your measurement

and set your die up to that, then your brass will be .004 long at least. at worst with an AR you are finishing the case sizing in the chamber with

the bolt being the press. In that case you are putting a beating on the bolt and may gall the back of the bolt and barrel extension.

At best you may have function problems.

With a Bolt gun you will probably have a hard to close bolt, but the same damage can occur.

Later

Good info, thanks!

[Powder Finger]

also a thought;

all this measuring stuff sounds like a PITA but not really. You do it when you set up a new rifle, tale notes etc.....

check it every so often(like your brass get work hardened and does not size the same)make more notes, then make an adjustment in your

setup that may accomodate new and older brass, or toss the brass it's probably toast anyway.

If you have to setup for more than 1 rifle and you use the same die press then here's the cool deal,

http://www.sinclairintl.com/.aspx/pid=33197/Product/Skip_s_die_shim_kit____7_8_14_

Now you just set your die up with a shim or two for your shorter chamber, then add shims to those to change the die height for your long chamber. Again keep notes.

[Powder Finger]

Jeeeeez I should get my head together today.....

If you order from Sinclair go through Brian's BROWNELLS link then click the SINCLAIR TAB.

Have not tested it yet but I think Brian get's "super special points" for those orders too.

End shameless vendor plug.........

[Chris]

http://www.ar15barrels.com/data/223-556.pdf