243 Headspacing Problem

[Werewolf]

I switched my wife's rifle from a 308 barrel to a 243 yesterday. This is my 2nd conversion, the first was a 30-06 to 25-06 that went smooth as silk after I gorilla'd the old barrel off. I bought a forster headspace guage (marked 308,243,7mm-08,etc.) and used it to headspace the barrel initially, but I found that none of my resized brass would chamber. I have been reloading for five years, and I miked the cases and know they are in spec, but no chamber. I ended up making a dummy round and used that to headspace the rig, chambers easy plain, bolt won't shut with a piece of scotch tape on the head, and put it all back together. I know that the headspace is set to brass out of the die that I will load for this gun with, but I am still bothered. Did I do something wrong, or will I run into a problem later? Anyone else had a problem with a multi caliber guage? I need a little voice of experience to calm my fears before I put this gun into my beloved's pretty (undamaged) hands :o.

[jinx-)]

Scotch tape? I thought its electric tape you should be using if no-go unavailable, also with electric tape one layer should be stiff, but turn-able 2 layers shouldn't close, but with scotch you need to add few layers, who know how many...

[Eric in NC]

, but I found that none of my resized brass would chamber.


308 sized down to 243? Did you trim it? Check the length of the brass. Doubtfull your gauge is out of spec.

[GUNFANATIC]

Scotch tape? I thought its electric tape you should be using if no-go unavailable, also with electric tape one layer should be stiff, but turn-able 2 layers shouldn't close, but with scotch you need to add few layers, who know how many...


One piece of scotch tape works perfectly. I headspaced a guys 6mm barrel with a go guage, one piece of scotch tape on the end for the no go. Worked like a charm.

[jinx-)]

get yourself a micrometer then measure thickness of single layer of scotch tape, I'll ease your pain its 0.0021" according to my mic, now you adding 0.002 to the length of the fired case? how many times was it fired, if it never been fired it will grow by 0.010" my brass usually hard to turn after 0.0045" and I never let it get that far so I FL size by bumping back shoulders no more then 0.002", electric tape on the other hand measures 0.0061", so that's what you have to aim hard to turn but still doable if you are using dummy round, as far as you headspace gauge you didn't specify which one you trying, there are like 3, go, no-go and field gauge, using go with on layer of scotch tape won't work since it only shows minimal length of the chamber, no-go can vary from one manufacture to another its just recommended length then a field gauge would indicate if you have an excessive headspace .

take a look at the highlighted line this is you max and min -0.007" so with go gauge you start at min and you have to work your way from it.

http://img593.imageshack.us/img593/3487/243saami.jpg

[82boy]

I found that none of my resized brass would chamber. I have been reloading for five years, and I miked the cases and know they are in spec, but no chamber...Did I do something wrong, or will I run into a problem later?

To start, buy some new brass, it is the cheapest thing in building a new gun. The first rule of thumb is new barrel, new brass. Your 5 year old shot God knows how many times and been re-sized brass has probably taken a set to the other chamber, there is probably enough spring back after it comes out of the die to keep it from chambering. Just because brass works in one chamber doesn’t mean that it will work in another and to boot just because your die is set up and works for one chamber doesn’t mean that it will work with another. It is hard to say if even your brass is in speck.
Yes many people have set headspace off of brass, and using 2 pieces of scotch tape as a make shift no-go gauge. What you are looking for is .002 clearances. If you measure scotch tape it will measure somewhere around .002 thick, so it should close on one piece but not on two piece thick. The problem with this method it is possible to force the bolt down and crush the tape, it takes a bit of feel. Electrical tape is way too thick with it measuring around .006-.007 thick. Another method is to go to an auto parts store and get piece of plasti-gage. (Used to measure engine bearing clearance.) They have different ones and the one you want is blue in color measures .000- .004 I think. Anyhow put a piece on the back of your brass close the bolt and measure the thickness with the package it comes with, if you got .002 clearance call it good, if you got more or less, then you have a problem.

[handirifle]

I'll go one farther, buy a box of new 243 ammo and test it. Even new brass has to be resized, so you wanna make sure your dies are setup properly as well. It only take a couple thousandths of extra length to screw it all up.

You DID screw the barrel down onto the GO guage, correct, and then tested with both GO and NO-GO guage? Also, on occasion, I have had to remove the extractor from the bolt head, to get proper headspace.

[jinx-)]

Patrick, you right again with electric tape I get ejector marks and tape get squished so its more like 0.004 or less, but its a tight fit... Also the carbon test with carbon smear on the shoulders, they should just touch at the bottom so there are still room for them to grow. If all carbon is gone the headspace is to tight, no marks then excessive headspace is your problem...

[Werewolf]

Wow at some of the replies. I have been reloading for my 270, 7x57, and 223 for years, not with the same brass. This time I was using once fired 243 headstamp brass I got from a forum member. I resized it fully by running the die all the way down to the shellholder, and when I measured the brass it matched the specs from the Hornady reloading manual(last edition not the newest one). I was using a forster go guage that they market for 308 family of cases, and when I screwed the barrel all the way down onto the go the 243 fully resized brass would not chamber. Now that I think about it I guess the main question I was asking is if the 243 and 308 cases are different enough to cause problems like this when headspacing using the same go guage. I don't really want to but a live round and stick it in there to test the chamber until I am reasonably sure it is safe. Again, my fully resized dummy round chambers easily plain and gets real stiff with one piece of scotch tape ( I didn't force it closed). This is the only 243 I have so I just bought the guage, dies, and bullets new. I am doing this build so that my wife can have her own rifle that she is comfortable shooting, and I just wanted opinions on what I did to make sure it was safe.

[Handloader]

Check the trim length on the brass, and is the bullet seated too long?
Also, did you check with the go gauge AFTER you tightened down the barrel nut? I have had the barrels turn a small amount when I tightened the nut down that threw the clearence out-of-spec.
I have found that I usually need more than the Full lenght sizing die just touching the shell holder and needs to be advanced greater than just touching the shell holder. The just touching method will generally work in store-bought guns that have a longer headspace. I find 1/4 turn or more after the die touched the shellholder is needed on a tight headspaced barrel. Perfect example..... I pulled a factory Savage barrel off a rifle that had the front and rear sights on it for muzzle threading, after putting the barrel back on the sights were of the original axis by 18-20 degrees. The original install of the barrel had "field" headspacing. Some reloads were too long to chamber in the same rifle, and had to have the shoulder bumped back farther to chamber.

[82boy]

I was using a forster go guage that they market for 308 family of cases, and when I screwed the barrel all the way down onto the go the 243 fully resized brass would not chamber... Now that I think about it I guess the main question I was asking is if the 243 and 308 cases are different enough to cause problems like this when headspacing using the same go guage.

No the 243 is the same as a 308, 7mm08 260 ETC. Trust your go gauge, place it into the chamber of the barrel, and put the bolt into the action with it closed, and screw the barrel down untill it stops, then lock the nut. Take your go-gauge and place 2 pieces of scotch tape on tha back of it and it will now turn it into a no-go-gauge, se if you can close the bolt. Forget about the brass. Dies will very in the amount that they size brass, and sometiimes they dont compleatly size the brass and need modification. (Redding is one that comes to mind.) Screwing the die down untill it touches the shell holder doesn't garentee that the die is set correctly, or that it is correctly sizing the brass.

[Eric in NC]

You said you miked the brass. Did you pull out the calipers and check length? You either have brass that is too long or dies that are out of spec or not set up right. Not doubting your experience but those are the only logical answers (or that you let the barrel move when tightening the nut down).

I am sure a bad gauge is possible, but I have never seen one or heard a reliable report of one.

[Werewolf]

I will recheck my measurements tonight when I get home from work just to be sure. Thank you all for your insight and ideas.

[stangfish]

My Money is that your die is set up to high. Some shell holders are different hights also. If you holder is bottoming out and you still have trouble cosing your bolt get a hornady LNL headspace gage kit.
http://www.midwayusa.com/Product/479704/hornady-lock-n-load-headspace-gage-5-bushing-set-with-comparator
http://media.midwayusa.com/productimages/large/479/479704.jpg

[gotcha]

The LNL hd sp gauge kit may compound the problem. They're good for showing the difference between unfired, fired or sized brass but are notoriously inaccurate for measuring ACTUAL size. The hole that accepts the shoulder of the case/ hd sp gauge must be the EXACT diameter specified in the SAAMI spec. or your ACTUAL reading will be erroneous. I'm having a similar problem to werewolf. .... 6.5X47 L hd sp spec = 1.4717" w/ caliper zeroed to gauge my go gauge reads 1.465" ???........... unfired,fired & f/l sized brass all read 1.465" (+or- .00025") My S/H measures .498" (.002" under spec) I can mill about .003" off bottom of die or mill .003" from S/H or re-set hd sp w/ .003" shim under go gauge. I elected to return H/S gauge to Mfg. for certification. I remembered Dave Muzz saying he had seen up to .003" difference in H/S gauge readings between mfg's. When I set H/S I put a witness mark across action, bbl. nut & bbl. to insure I had no movement of bbl when torquing bbl nut. Still waiting for feed-back from mfg on H/S gauge. ............ any comments welcome :) Dale Werewolf, sorry for butting in :-[

[stangfish]

Dale,
From the data you provided, I know you have some value in your point but I am missing it. I think the fault lies with myself as I did not do justice to my position. If new ammo fits but resized does not, more than likely the sizing process was incomplete or done incorrectly or the headspace adjustment needs to be checked. If the shell holder bottomed out against the face of the die and the bolt is still hard to close then I deduced that the headspace is off. Using the LNL headspace gage would prove that. What it would not do is verify if your headspace gage is out of tolerence. I have never put a HS gage on a sign bar to verify its angle but I have some headspace gages from Shaw that the angle nor the diameter resemble any of the deminsions on the cartridge on the buisness end of the gage. This one fits all 308 based cartridges and the case is a 7mm-08. It has proven its accuracy on 308 and 260 barrels double checked with a set of clymer gages after the fact.

http://i1202.photobucket.com/albums/bb363/stangfish/100_58782-2.jpg

If the angle is the same in the chamber and the sizing die, you are getting a good reference. A reference is all you need to determine if headspace is correct regardless if the it is from a bad gage, bad chamber or poor tolerences with the die. I will admit I am not a first class machinist but I am turned some metal and precision ground some close tolerence stuff. Please explain what you mean that "it could compound the problem." My analog Brown and Sharps arent good enough to pinpoint .00025. I dont think they need to be to solve this type of problem given the fact that common hunting rifles can vary up to .004 in headspace clearances. Im sorry if I miss your point but I wanted to clarify mine.

[bigedp51]

The last batch of .243 cases I bought had cases as short as .009 below minimum headspace, so you should never use a case as a headspace gage. Just dry firing a fired case can drive the shoulder forward .001 when you pull the trigger. This is why you are told in the reloading manuals to not use cases loaded for reduced loads with full power loads because of cartridge headspace being too short.

A resizing die is (theoretically) designed to push the shoulder back .002 below minimum headspace when touching the shell holder.

If you slowly chamber a new unfired cartridge case with a spent fired primer in the primer pocket the amount the primer is protruding is your head clearance or the "air space" between the bolt face and the rear of the case.

You need new cases and a means to measure your new and fired cases.

http://i122.photobucket.com/albums/o254/bigedp51/IMGP7241.jpg

And below is why you should never use a new case to set headspace.

http://i122.photobucket.com/albums/o254/bigedp51/twocases.jpg

[Werewolf]

No problem Dale. It's good to know I am not the only one. :)

BTW I am waiting until my days off so I can pick up some factory rounds. Then I will at least have something to compare my reloads to. Then I am going to take it all apart and try again. I will not let my honey have it until I am sure it is good.

[gotcha]

Stangfish, 1st, thanks for the reply :) To answer your question i should have used the word " questions" instead of "problems". As many suggest, werewolf could benefit from going back to new unfired brass. This would confirm the sizing issue is either the HS gauge or the F/L die. Can't rule out a too tall shellholder either. The point I was trying to make is the comparator is designed to provide only a comparative reading not a definitive reading. With the.308 hd sp spec being .007" in range you may achieve a reading that falls somewhere in that range w/ a comparator. So, it would seem we're in agreement w/ the capabilities of the comparator :D It would take a much more sophisticated measuring device, as you mentioned, to varify the true dimensions of a go-gauge (sign bar or whatever) so, I think we're still in agreement :D.............. I think? With the concerns I have on the 6.5X47L I thought it logical to chk. the specs on my go gauge before jumping willy nilly into grinding sizing dies or S/H or shimming H/S gauge. The H/S spec range on the 6.5X47 is only .002" so all the components we've discussed must work in harmony. Your input & concerns are appreciated ;) Now, if I can just figure my problem out ??? Dale

[gotcha]

werewolf, No doubt you'll be an expert in HD spacing when this is all over ;D The suggestion to buy the Hornady LNL tool is excellent advise you can use it as a HD space comparator or w/ the same tool switch to a bullet comparator and get really consistant seating depth readings. Since I got one I wouldn't be without it. Let us hear what happens w/ the new factory ammo.