Small base dies case stretch ar-15

[8185854610]

I have noticed that Rcbs 223 small base dies are stretching my lc 2013 cases..
New case fired .001 to .002 length increase when fired in ar-15. I measure the case and size it with a small base die set correctly for .002 shoulder bump.
The case stretches .005 when sized. Now the case is 1.756, original length 1.750 +.001 from being fired and + .005 from sizing.. Fired only one more time and I am at 1.762. Trim is know necessary. So two firing with small base die and must be trimmed.

A guy at the range uses same exact gun and load lc 2013 case, Hornady fmjbt 55 grain 26.0 grains blc-2 and light crimp. He uses std fl dies works fine in his gun. He could not recall how many times fired before trimming.

My question is if you have no malfunctions using std fl dies about how many times fired before you hav to trim your cases.

[J-cat]

The sb die is not causing your cases to stretch. Firing in your AR is causing them to stretch. The reason your buddy is not trimming his brass is because a 556 chamber is .050" longer than min trim length. That means 10 reloads before the case is too long.

[8185854610]

Both guns ar 556 as is the ammo lc2013 cases are 556. As my post reads firing a new case that is 1.750 long stretch to 1.751 to1.752 after sizin in small base die they stretch another .005. But thanks

[bazineta]

I guess the first question is, is your chamber undersized such that you need to use a small base die?

Reason I ask is that I run LC brass that's been fired in M240Bs through standard Redding dies, and the results are in spec; while I have small base dies, I've never needed to actually use one.

[J-cat]

Both guns ar 556 as is the ammo lc2013 cases are 556. As my post reads firing a new case that is 1.750 long stretch to 1.751 to1.752 after sizin in small base die they stretch another .005. But thanks

You can't compare his fired brass to your resized brass. Resized brass will always be longer.

[fguffey]

=8185854610;19518089]I have noticed that Rcbs 223 small base dies are stretching my lc 2013 cases..
New case fired .001 to .002 length increase when fired in ar-15. I measure the case and size it with a small base die set correctly for .002 shoulder bump.
The case stretches .005 when sized. Now the case is 1.756, original length 1.750 +.001 from being fired and + .005 from sizing.. Fired only one more time and I am at 1.762. Trim is know necessary. So two firing with small base die and must be trimmed.

There is a lot that happens between pulling the trigger and the bullet leaving the barrel reloaders do not understand. I have not given up on believing the reloader understands the case does not have head space and the case has two length; one from the end of the neck to the case head and the other from the datum to the case head. And then there is the perception they are able to move the shoulder; reloaders always start with :I BUMP...", and I always ask: "HOW?". NO one answers me, they just get mad or angry and snarky.

If reloaders would think about 'IT' they would understand the die does not stretch the case, the only direction brass moves is toward the neck. Not my fault but reloaders believe they can move the shoulder. Moving the shoulder is a bad habit. I find moving the shoulder is most difficult, it is easier for a reloader to claim they move the shoulder than it is to move the shoulder.

There are reloaders on the Internet that claim they have case heads that are not against the bolt face when the trigger is pulled, when an internet reloader tells me their case heads are not against the bolt face I tell them there is nothing they can do to prevent case head separation if the case head is not supported; and, they have no clue what all of that is about.

Back to the distance from the shoulder/datum to the case head, every reloader insist they move the shoulder and I ask; HOW? How can a reloader move the shoulder of a case? I can not move the shoulder of a case with a die that has case body support. I know, "Yes I can" is not an answer. I can not move the shoulder of a case with a die that has case body support; Why?

I can move the shoulder of a case with a die that does not have case body support; What is it a reloaders does not understand about moving the shoulder when firing and sizing?

F. Guffey

[8185854610]

I am not comparing his brass to mine. he reloads also using regular fl dies and i am using small base. After firing I am taking meadurements of my own.

I am trying to find out what other people find the number of firings are before trim using std fl dies.

Also the brass I am using started out as new not once fired lake city. Thanks

[mike.h]

I tried the small base dies for my .223 wylde chambered AR, but felt they overworked the brass. I now use the redding FL resizing die.

[J-cat]

The only difference between a regular and small base die is the sb die is .001-.002" tighter at the base. That little bit does not induce .005" of case stretch.

Second, unless you are measuring both his and yours before assembly and after resizing your comparison is invalid. New brass varies in length more than that.

[the86d]

Do RCBS X-DIEs really work for not trimming as often, or at all?

[someoneeasy]

To avoid this problem, I use this secret technique that most reloaders try to avoid. Ready for it? I trim my brass after every firing!

No measuring and sorting or wasting time to keep track of how many times a case has been fired, just clean, trim, load, shoot.

It seems like you waste more time trying to measure and avoid trimming than just running it through the trimmer. I dont need to add another step in my process to slow me down, I just run it through the trimmer. If it only trims a little bit, then it trims a little bit, if it trims more, then it trims more.

[8185854610]

Any idea how many times fired with fl dies befire necessary to trim, thanks for your input

[8185854610]

Thanks i re-read you post

[J-cat]

Any idea how many times fired with fl dies befire necessary to trim, thanks for your input

My chamber is 1.795" long. So from 1.750" it will take 8 reloads.

[racinjason233]

[QUOTE=someoneeasy;19519181]To avoid this problem, I use this secret technique that most reloaders try to avoid. Ready for it? I trim my brass after every firing!

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