primers backing out

[krallstar]

Hey all. I have been loading 180gr cast for a Ted Williams 30-30. I am using 10.1 of power pistol and getting 1500fps. My question is the primers seem to back out a little after firing. Primers look good and no signs of over pressure. Is this a problem.

[Dan Cash]

Probably not a problem but may be difficult to insert brass in shell holder for reloading. I am not familliar with your propellant but backed out primers are usually indicative of low pressure.

[M-Tecs]

It's under pressure. The case is not pushing back against the bolt face to reset the primer. Common will low pressure loads.

[Ballistics in Scotland]

If the primers aren't being mushroomed or pushed back again, or being extruded far enough to show that your rifle has excessive headspace, this is entirely harmless. My Winchester 86 with moderate loads extrudes its primers by the .005in. of its safe and normal headspace. This just shows that the pressure is momentarily born by the brass and its grip on the chamber walls, without being stretched or separated.

[mud_alaska]

krallstar - From my experience and reading up on the issue it is not a problem. I experience the same thing with my small game loads in my model 94 Winchester. From what I understand the reason for it is there is not enough pressure to force the case against the bolt face there for the primer backs out from the primer pocket a little bit. With that being said you could also have brass that is heavily used and the primer pocket could be enlarged. With the light powder charge you are using I would think its the not enough pressure. I'm not suggesting to load heavier, I'm saying the primers backing out is not an issue!!! Justin

[Vann]

Like Dan Cash said it's probably just an indicator of low pressure. A picture would be a great. In a normal pressure load to primer is blown out of the case a bit then crammed back into the primer pocket. This is why most primers are flat when firing factory ammo. Unless it's causing problems you are probably OK, you can try moving your load up and down a bit if it's causing problems. My Savage 170b seems to do this a lot until I start pushing it.

[newton]

yep, I've had it happen to me too. I put them over a chronograph and the velocities also showed that it was because of low pressure.

[krallstar]

Brass all once fired. This was a starting load. Powder has similar burn rate to unique just a tad slower. Planning on slowly upping charge. Will post a pic soon.

[Artful]

So picture if you will - an explosive pellet in a cup in a pocket with a small hole to expel the flame and gases when it is set off - this pushes the cup out of the pocket forcing the case forward pushing on the shoulder of the case. If there is enough pressure generated in the case the brass is pushed back down over the cup and the shoulder is expanded to the limit of the chamber. If not enough pressure you have the primer sticking out.

Now you have several courses of action

If you just want plinking loads with small fast burning powder

Just up the charge or change to a different powder burn rate.

If your trying for Subsonic loads...

- one is to segregate some brass to be used only with your subsonic loads and open up the flash hole so that more of the pressure can escape into the cartridge without pushing the primer out. The down side is these cases can never be used with regular powder loadings again because it will let more high pressure back into the primer pocket than it can contain.

Another is to adjust your load to increase the pressure so that the primer is reseated by the load and the should blown forward as in a normal supersonic load. This is a balancing act if you want keep the boolit subsonic. I find it best to use heavy for diameter boolits to do this.

And lastly you can use a cartridge case that is more solid - expensive to have cases machined but you can then lower the capacity and make it easier to have a full case of fast powder and still achieve subsonic loadings.

[paul h]

Sounds like you are setting the shoulder back when sizing the brass. Try partial sizing different once fired cases and see if the primers backing out goes away.

[gunwonk]

Brass all once fired. This was a starting load. Powder has similar burn rate to unique just a tad slower. Planning on slowly upping charge. Will post a pic soon.

As pretty much everyone has pointed out, it is not a problem that your primers have backed out and stayed backed out. It just means that there wasn't enough pressure to stretch the case, and push the case head back over the primer.

Because this is a .30-30, it headspaces on the case rim. So you don't have to worry about your cases gradually getting shorter when used with a light load. The rim will prevent that. You can use as light a load as you like, and the only issue would be making sure your load was sufficient to get the bullet all the way out the front every time. :)

Also, the amount by which your primer sticks out is a quick and dirty way of measuring the headspace of your rifle. You'd like to see it about .005" or so.

Bottom line: don't worry about it, unless you want heavier loads for another reason, or unless your primers stick out more than several thousandths (in which case the rifle has a problem, not the reloads).

[krallstar]

Also, the amount by which your primer sticks out is a quick and dirty way of measuring the headspace of your rifle. You'd like to see it about .005" or so. This is about or a little less protrusion that i have. Closer to .003

[gunwonk]

Also, the amount by which your primer sticks out is a quick and dirty way of measuring the headspace of your rifle. You'd like to see it about .005" or so. This is about or a little less protrusion that i have. Closer to .003


.003" is good! Headspace is basically the distance that a cartridge could rattle back and forth in the closed chamber. (Yours went "forth", but not "back". Only the primer went "back".) Some accuracy buffs have run experiments that suggest .002" is the best number, if you can get it. I'd certainly settle for .003". If it had been .006", or .010", you'd have probable cause for a headspace inspection. But you don't. Enjoy! :)

[krallstar]

Those are the dies i am using. Also the brass is R P. From reading on the web i see this brass is kinda soft.

[Wayne Smith]

I recently bought a 7x57 Interarms Mark X...beautiful rifle and looked like it had not been fired much..I did not check headspace. I got a bunch of primed brass with it and went ahead and loaded them up with a "ladder" of book loads with 160 grain Speer Jwords which is a fairly common loading.
Shot them and was well pleased but when I got home and really started to give the brass a close inspection I found that the primers were about .004-.006 proud pretty much across all the fired brass.

I was "advised" by a couple of old time 7mm Mauser guys that the Interarms action is very strong and no sweat to "load it up" a bit and that would correct the issue...I did load a bit warmer (not over max) and still had the protruding primers...Took the rifle to a smith and had the headspace properly checked with the extractor removed and the bolt body "naked", etc....the rifle has excess headspace...swallows the go gauge...will also barely close on the no go and will not even begin to close on the field gauge...Smith said he'd had much experience with this kind of situation and unless I planned to shoot it "daily" I'd probably never get in trouble...suggested I only neck size (it's the only 7mm I have) and load moderate loads....he suggested the Lee Collet dies which I picked up...I'm on the 5th loading with the neck sizing and I have no issues with proud primers and absolutely no issues with any indication of any pending head separation....works for me and saved messing with a rebarrel or just selling the rifle which I really like...I like the Lee Collet dies and my accuracy and consistency of groups is just fine for me.

When you neck size only you are maintaining the shoulder established by firing in your chamber and you no longer have a headspace problem. You can be comfortable loading to full power loads with this brass as it fits your chamber perfectly. The only cost is a slightly shorter neck.

[opos]

When you neck size only you are maintaining the shoulder established by firing in your chamber and you no longer have a headspace problem. You can be comfortable loading to full power loads with this brass as it fits your chamber perfectly. The only cost is a slightly shorter neck.

Mine or the brass's neck?..lol...it shoots way better than I can with nice moderate loads.

[Wayne Smith]

LOL - Well, I was thinking of the brass, but if your stick yours out too far....

[BAGTIC]

Did the gunsmith tell you exactly how much the headspace was? .010, .020, .30, etc.. I had a similar problem with an Interarms Mark X 7x57 AI` and it turned out that whoever had set the rifle up initially had used an 8x57 headspace gauge as it 'right on' for the 8x57.

[Artful]

Forster offers three lengths of headspace gages per rifle caliber.
In order from the shortest to longest, they are: GO, NO-GO and FIELD:


GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gage, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gage is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gage is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
NO-GO: Corresponds to the maximum headspace recommended for gunsmiths chambering new firearms. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gage, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gage. The NO-GO gage is essential for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gage, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gages are slightly shorter than the SAAMI maximum in order to give a small safety margin.

http://saami.org/specifications_and_information/publications/download/206.pdf
see page 26

257 Roberts, 6.5 x 257 Roberts, 7mm Mauser (7 x 57) all use the same head space gauge the 8x57 uses a separate gauge.

My Forster .30-06 headspace gages and the difference between go and no go is .006"

[Retumbo]

http://i122.photobucket.com/albums/o254/bigedp51/HeadClearance_zpsf30a3af1.gif

[opos]

Did the gunsmith tell you exactly how much the headspace was? .010, .020, .30, etc.. I had a similar problem with an Interarms Mark X 7x57 AI` and it turned out that whoever had set the rifle up initially had used an 8x57 headspace gauge as it 'right on' for the 8x57.

First he stripped the bolt which is the right way to do it..then a super thorough cleaning in the throat, chamber, etc..the go gauge did what we would expect no issues..just "dropped closed". The no go allowed the bolt to close with very light finger pressure on the bolt handle but there was some "drag" experienced...using the field gauge with very light finger pressure on the bolt handle the handle barely moved at all...his comment was the measurement was a "fat" no go gauge and plenty safe using the field gauge...he did do one thing (and he said it is not something that he recommends for the "layman" was he took the no gauge and put one layer of scotch tape across the head and trimmed it to fit...then again with just the least amount of 2 finger pressure on the bolt so as not to cam and mash the tape...the bolt would not close on the no go...

His diagnosis was about what the primer protrusion was..about .003 or so...his comment was "do you want to sell me the rifle?".. answer was no....his comment was to use the Lee Collet dies or other headspace techniques to marry the brass to the chamber/throat...I only have the one 7mm Mauser so no problem of interchange to another rifle...He also suggested that it would not hurt to load moderate loads that find decent accuracy..I have found that big booming full house loads don't normally give me the best accuracy and that proved here..

I take PPU loaded commercial ammo..fire it to get the brass...don't use anyone elses brass...I clean, neck size..verify length and trim (I trim about .010 short if it's long). I take each of the sized and trimmed cases and check the fit in my rifle...don't want any surprises after they are loaded...95% of the time everything is just perfect..I have had a couple of cases that were just a tad tight and put them back through the sizing die and they seem to work great...When I load I seat the bullet in about 3 steps...first just a touch to start the bullet..rotate the case a bit...a bit more seating...rotate again and set the bullet home..never seem to have any runout issues.

The rifle shoots way better than I can shoot it..it's really a beautiful rifle..it's one of the Manchester England models and has great wood and the bluing looks like a Python blue....

Interesting bit of "aside" info...when I was into my mania about headspace and safety I got hold of Hatcher's notebook and read up on his comments about headspace...really interesting and gave me a bit of ease....

I have a Winchester model 1917 Enfield that was marketed by Sears ...they bought up a bunch of military and commercial actions...had them barreled and stocked, etc by a company in Chicago and sold them as a "price" rifle in the 50's and 60's....they are not, as some folks think, a bubba conversion of a military rifle..they were made to be what they are using actions they could get...

Being an Enfield and I'd bet with very little use from overall condition...it still is just a tad generous in headspace...the no go will let the bolt close with some drag (no force!) and the field won't allow the bolt to even begin to close..again all this with the bolt body stripped so no extractor or bolt friction involved..this amount of "slop" seems to follow with most U.S. 30 caliber bolt action rifles...the gauges for them were a bit different in spec than the modern Forester gauges from what I have read and heard..

The smith did say a couple of things..he said often people try to check headspace without stripping the bolt...his comment was if the rifle is in really good shape with no issues that might be reasonable but in a case like mine where we knew there might be a slight issue he didn't want anything to affect his measurements...he also said "2 fingers" and absolutly no attempt to push to close the bolt on the gauge...just let it sort of "find it's place"...the pressure generated by the cam action (especially in things like the Enfield) can ruin the gauges and also give very faulty readings...while I watched him it was a very gentle and almost dainty (he kick my butt if he heard that) process...I always thought it was more of a "jam the gauge in the chamber" and see if you can close the bolt even if it took some force...not a good idea.

One final, final thing..I check each piece of brass very closely for any external indication of possible head separation..no ring on the case and no shiny or odd looking areas...I also "feel" the inside of the case with a sharp dental pick like the cleaning person uses on my teeth..I have not felt or noticed any indication of ridges or divots in the brass..if I should then the brass goes in the recycle can...The smith said he often sees rifles that will show the beginnings of headspace separation after just a very few firings..some of my brass is now on #4 or #5 loadings and is fine...being "belt and suspenders" cautious I'll probably never get penny wise and pound foolish trying to stretch the usage...any odd stuff at all and they are gone.