Head-space - Pressure - Primers

[mag_01]

Hopefully pictures will show 1st stage signs of head-space problem --As well as primer flatness due to pressure.

[mag_01]

Cases with an X have primers backed out somewhat which is the first indication of head space problem -- 2nd stage primers appear normal and 3rd. stage is case separation. those cases in 7.7 jap had 18grs. of 2400 behind a gas-checked 180gr. fat boolit. Case on left shows flat primer and case also shows imprints from the corroded chamber. Case on left was 17grs. of 2400 no gas check but a solid type filler (ground walnut) and the 180gr. boolit. This round had (pressure) --- To open bolt I had to use a hammer --- primer very flat and imprints of chamber on case. ----- Mag

[smokemjoe]

Mag 01, Start a primer in the case and close the bolt on it, That will tell you also how much headspace you may have, I have a 303 British that had .030 to much headspacing, I soft solder a piece of tin on the bolt face . Dont get the bolt over 400 Deg. Worked great and still using it. Smokemjoe

[Char-Gar]

Whoa.... Do not use a solid filler with powder charges of such a small volumn. That much filler will add enough weight to the ejecta to cause the pressure problems you experience.

17/2400 is a very mild load that is not going to cause in problems in your rifle.

The filler is the source of your problems!!!!! 2400 does not require a filler. Solid fillers should not be used unless the power charge occupies at least 60 - 70 % and perhaps more of the available case capacity.

With fast powders like 2400, 4759, 4227 and the like SOLID fillers present more problems than they solve.

I don't think I would draw and conclusions about headspace, etc, until you try that rifle with correct loads. You might come out at the same place, but then again you may not.

Primeres backing out are not always caused by excessive headspace. Often it is but other times, it is just inadequate pressure to reset the primer against the bolt face.

A line around the case head also does not always indicate a case head seperation in the making. To detect those things, it takes a wire feeler on the inside of the case.

If you want to know about the headspace of your rifle, buy a Wilson case guage. Neck size a fire case and drop it in guage. Take a look at the steps on the head end of theguage and you can get some notion if the rifle headspace is in spec or not. If the neck sized fire cases won't go in the Wilson gage, then just partical size the body until it will. Just make certain the case shoulder does not contact the sizing die. The Wilson guage cost much less than a headspace guage and will also give a wealth of other information about your rifle and loads.

[45 2.1]

Do not use a solid filler with powder charges of such a small volume.
Good sound advice for fast powders....!

That much filler will add enough weight to the ejecta to cause the pressure problems you experience.
The actual problem, not that the filler doesn't add additional weight because it does, is the the filler reduces the actual combustion area for the powder to burn making the cartridge in effect a smaller cartridge in which you have introduced an overload, if you go too far.

[mag_01]

SmokemJoe --- Thanks for the suggestion --- May give it a try --- and thanks all who contribute information. I have done a lot of work with fillers (solid fillers). I almost feel the hard bolt opening was mostly due to chamber condition and of course pressure from filler. If you look closely at case It most definitely gives signs of badly pitted chamber lots of rust there also. As far as loads. The previous owner gave me cases from full power loads with J bullets and primers where backed out as well. The solid filler did add pressure as I was trying to show---- my pictures where not really as good as I would like them. Joe I have done a few bolts to eliminate head-space problems. Welding 1 lug at a time and fitting it back to action. Another rough method I use for checking head-space is to apply solder to back of case then fitting and inserting it back in chamber. In general I was hoping my pictures would demonstrate 1st stage head-space as well as pressure signs. --- Mag_01



Is your (Job) bothering you --- Take two weeks off then quit.

[Bret4207]

I too have seen underloaded cases give the same result. I often wonder about headspace and why it is such an issue for so many folks. (Gonna get fried for that sentence) I'm sure many of us have accidentally induced headspace issues by over sizing brass, failing to note actual chamber sizes etc. I have a SMLE that has the typical generous chamber. If I FL resize my brass and use a lite load I get a backed out primer and smoked case. If I use a long enough booilt ans seat into the throat I get nice, safe fireformed brass that lasts good. It's a matter of working with what you have.

Now, the above applies to bolt guns mostly. If you try this with some springier actions like a Win 94 you may not have success. Or if you have a true problem headspace condition, like my Win 43 218 Bee where the bolt lugs are slightly set back due to a previous owner trying to make it a 220 Swift- well then we have an issue that needs fixing. (The 43 will get electroplating on the lug recess/lug area.) Eroded chambers as described are another problem that I have experience with. Unfortunately my fix didn't work at all. Sometimes the only solution is a trip to the gunnysmith or a new barrel.

My rambling, incoherent post is intended to put forth the idea that in some cases headspace , handled properly, results in sort of a wildcat case that you can work with. YMMV and I'm not advocating anything unsafe.

[PatMarlin]

Question...

Is some primer flattening always a dangerous pressure sign?

[felix]

Yes and no. No when the load is known to be hot, like intentional coming up from below. Always hard on the primer pocket, but not the heavy duty gun. Any other time requires strong investigation as to why. Headspace? SEE? Loose primer pocket? Soft case? Soft primer? ... felix

[PatMarlin]

My VZ-24 Mauser in 358 win, is flatening the primers some. I'm loading 39grs of Mil Surp 4895 which should be a safe load behind a 245gr saeco. Large Pistol primer. Bout' 90 percent powder filled case. It is very accurate, now shooting 1" @100.

I have the OAL set into the lands. Using Lee fact crimp. Over crimp maybe? Boolit is about .001 over groove dia.

I'm clueless.. :confused:

[Maineboy]

My VZ-24 Mauser in 358 win, is flatening the primers some. I'm loading 39grs of Mil Surp 4895 which should be a safe load behind a 245gr saeco. Large Pistol primer. Bout' 90 percent powder filled case. It is very accurate, now shooting 1" @100.

I have the OAL set into the lands. Using Lee fact crimp. Over crimp maybe? Boolit is about .001 over groove dia.

I'm clueless.. :confused:


Aren't pistol primers cups softer than than those of rifle primers? You might try LRs to see what happens.

[DonH]

Had problems of primers backing up somewhat and near case head separations with a .338-06. The problem was that the case did not fit the chamber properly and would move forward under striker impact which then allowed the case to stretch backwards. Necking the case up to .35 then back to .338 leaving a bit of larger neck held the case between chamber shoulder and bolt face causing the case to fire-form properly. Both problems went away.
This may not have any bearing on the problem in discussion but it is worth considering, especially hwere a generous chamber may be involved. It ids in line with Chargar's comments re: using the Wilson case gage.

[Bret4207]

Aren't pistol primers cups softer than than those of rifle primers? You might try LRs to see what happens.


Not just pistol primers, but different brand primers will give different results. Factory Remington 6.5x55 always shows a flattened primer in my Mauser. Winchester doesn't. Federal primers flatten more easily than CCI IIRC. CCI's will easily pierce in one gun/load combo I have, Federals don't. Each gun/load/combo is a law unto itself.

[PatMarlin]

Thought about that too, but it does it with WLR's and the pistols were CCI. Groups seemed to shrink up a bit with the LP's.

I need to have Lee make me a collet die. Setting the OAL max kinda takes care of a headspace problem doesn't it? Anyways I had a gunsmith check the headspace when I bought it.

Come to think of it, when I bought it- the stock was not inletted for the bolt properly, so the bolt would not set down all the way. That's when the smith checked the HS. Then I found the problem with the bolt and I ground out the stock so the bolt locked all the way forward.

What change if any would that have made, and shouldn't the gunsmith have caught that? Maybe he was drinking that day... no wait a minute, this is California. He coulda been smoking.. :roll: :mrgreen:

[454PB]

I agree with Bret, most all cases of minor excessive headspace can be controlled and adjusted by using the case sizing die. I'm a little less comfortable with controlling it by seating the boolits long. I've seen other shooters eject a loaded round, leaving the boolit firmly lodged in the throat.