Bulge near base of the case after firing

[lonniemike]

I'd be real surprised if the pictured case isn't experiencing incipient separation.On the case's right side-opposite the circled left side- there is an ever so slight case wall indentation. An interior picture of that case split open might tell a tale.best-o-luck

[giz189]

Listen to Nnobby45. Screw your die out enough that the case will not chamber, then screw it down a quarter or less of a turn until it will chamber with just a little pressure on the bolt hand to push it down. Not a whole lot, just a little. It really looks like your case is stretching like the die is bumping the shoulder down to much. I have noticed all die manufacturers tell you to screw die down until it touches the top of the ram and then a little more. I did this for years. Also, I had the problem you are having. You could see the mark and after a couple more loads or less, you got the bulge. It was then the idea of headspace in the chamber came to me. The case stretches to fit the chamber, When it stretches the line you see is where it stretches. Sooo, if you don't push the shoulder back or make the case shorter when you resize it, it doesn't stretch. At least my cases quit having the shiny line and bulges afte4r I started resizing like this.

[Nnobby45]

[QUOTE]

I'd be real surprised if the pictured case isn't experiencing incipient separation.On the case's right side-opposite the circled left side- there is an ever so slight case wall indentation. An interior picture of that case split open might tell a tale.best-o-luck

That's a good observation, Lonniemike. I've mentioned it more than once on this thread to no avail (I referred to it as a ring). Guffey recogognized it for what it is, also. A case that's gonna blow.

.

[GrumpyOldTex]

I think your chamber may be a bit oversized and it may have a little too much headspace. This causes the cartridge to fit loose in the chamber and when the gun is fired, the firing pin drives the case forward until it contacts the chamber shoulder. The cartrige fires and pushes the case head backward against the bolt face stretching the brass just in front of the head. The brass weakens in this area and eventually separates. I think the bulge is caused by the cartrige laying on the bottom of the chamber and expanding upward on firing. A gunsmith can check you rifles chamber with a headspace gage. This condition can be corrected by a good gunsmith but I would try fitting (fire forming) some cases first. I have a couple of rifles that i bought new that had slightly oversized chambers and it worked well for both of them.
1. Before investing a lot of money, I would pull the bullets from a few factory loads and weigh the powder charge in each. Write down the powder weight. Save the powder and bullet. I would also place the cases in my rifle and pop the primers. I don't like decapping live primers.
2. Now you want to expand the neck on your unfired case up to the next size. For a 270 you want to go to 7mm. To do this just borrow a set of 280
or any 7mm size dies, screw it in your press and and run the expander ball down through the case neck only. DO NOT RESIZE THE WHOLE CASE.
3. After this is done, screw your 270 die on your press and back it up at least three rounds from where you have been resizing your brass.Don't lock it down yet.
4. Get a case that has been fired in your rifle and has not been resized. Using a Bic lighter or something similar, smut up the neck and shoulder area of this case.
5. Place the case in your press and resize the neck. You will see where the die has wiped the smut from the case neck. Adjust the die and resize the neck until the shoulder in the die just touches the shoulder of the case. Back the die up one round.
6. Resize one of the new cases at this setting. This creates a "double shoulder" which seats against the base of the throat in your rifles chamber. Place the case in your rifle and close the bolt. You should feel a slight resistance when camming over the bolt. If you feel no resistance, back the die up 1/2 round and try another case. If the bolt won't close adjust the die down a little at a time till it closes.
7. Once the die is adjusted. lock it down and resize the remaining new cases.
8. Reload the cases with the original powder weight and bullets and go shoot them.
9. If your cases look OK readjust your die and reload them again. Readjust your die by smutting up a case you just fired and adjusting your die down until it just touches the shoulder.
10. All new cases for this rifle should be formed in this way. Always start with new unfired brass. I like Winchester brass from the same lot in quantities of at least 50 cases.
This is the P.O.Ackley tried and proven way of fire forming cases. I hope it helps your situation. Any questions feel free to ask.
Happy shooting
GOT

[SL1]

Rdjordan,

I have not been following this thread and will admit right here that I have not read all of the posts to-date.

But, from looking at the pictures you posted, I see the following:

On the fired factory ammo case, there appears to be a ring of different colored brass around the case wall, just ahead of the solid base section. This might indicate stretching of factory ammo cases, which would mean a gun headspace problem, if true.

On the fired handload case, the same ring appears, and within it, there is a thin ring with a smaller diameter. THAT definitely indicates that the case wall is stretching and is about to separate. You can confirm that by sawing a case (one with the thin ring of smaller diameter) in half lengthwise so that you can see the wall thickness along the length of the case. Sawing a once-fired factory round the same way might not show much, because the part of the case wall where the stretching occurs in initally pretty long (the length of the color band) but later firing stretch only a small part of the area previously stretched (like the thin ring on the fired reloaded case).

From these two things, I really think your rifle has a headspace problem. You should get it checked by a gunsmith and corrected if true.

You may also be adjusting your seating die too short. As others have written, ON A RIFLE WITH PROPER HEADSPACE, you still need to make sure that you are not bumping the shoulder of a bottleneck cartridge back when you size your case. That creates under-length case bodies that result in the same headspace problem and case separations that an over-long chamber creates.

Although it is possible to live with a SLIGHTLY over-headspace action, the marks on you once-fired factory brass indicate to me that your rifle is probably more that slightly over the "no-go" headspace. So, I STRONGLY recommend that you have a gunsmith examine and fix it.

SL1

SL1

[SUperMidget]

rdjordan:

Using TSX as base data is probably a good start as those are another of the vunderboolit breed that has a long bearing surface. However, backing off a bit is never a bad idea as long as there is enough powder in the case.

I would definately have a 'smith check the headspace on the rifle. If that checks out have him take a look at the contact between the secondary shoulder and the H-collar in the action. Some barrel manufacturers shot chamber mauser barrels and leave the threads shorter than need be with the intention of having the gunsmith doing the chambering turn the primary shoulder back on the barrel shank for the proper crush fit on the reciever ring. A gunsmith who is unfamiliar with the mauser series can forget to turn this back properly leaving a few thousandths gap between the barrel tennon and H-collar where the case is unsupported ahead of the casehead webbing.

[rdjordan]

I went and had a short chat with the 'smith this afternoon. He said just by lookin at the cases and the action/barrel combo that he thought it was probably an oversized chamber. He said that Interarms often sold the action and barrel combo and put that production piece together sloppily, leading to the chamber being reamed out too much. I also asked him why the case had more of a bulge on one side and he said that maybe the reamer didn't stay centered and would cause the chamber to not be perfectly round.

He was busy this afternoon and didn't have enough time to check the headspace but I am going to go back next week and he said he would check it for me.

He suggested that if the headspace was fine that I just 'deal' with the oversized chamber, for it would not be worth trying to fix.

I'll let everybody know what he says next week when we check the headspace.

[PCJim]

RD, you did the right thing by seeking first hand advice from a 'smith. Keep us updated.

[rdjordan]

Thanks, keep in mind that I live in MS and that I had to drive to the middle of no where, take 3 rights and 2 lefts, then a few miles down a dirt road to find this guy. But he says he has 45 years experience and he looks like it.

[GrumpyOldTex]

rdjordan
i was just wondering if your gunsmith has been able to check the headspace of your rifle yet. i also was wondering if you have tried fire forming some cases. if your headspace is excessive, fire forming can correct the problem. my explanation may have not been clear to you. try looking up fire (forming cases) on a web search.
GOT

[rdjordan]

GOT, I am planning on getting the gun smith to check the headspace tuesday or wednesday. I am waiting untill I go see him to figure out what my next move is, but I think fire forming may be the answer. If all else fails, I guess I can just shoot the brass one time.

I will let yall know what the gun smith says.

Thanks, Durham

[GrumpyOldTex]

[Gbro]

Durham,
What a wealth of information we now have at the end of a wire

I struggled with the same issues 25 years ago and had only limited information that I could find. Undoubtedly there were reloaders that had the info but we couldn't access this valuable knowledge very easily.
I scrapped out lots of brass with head case cracks, and only had 1 separation and that was not a direct result of excess headspace.
I for many years would set my .270win speer FL die with a dime between it and the ram. This resulted in getting many reloads out of brass before case lenght was an issue.
The only actual problem I had with this method was a consistant snug fit, as some loads took a little more push to close the bolt and when it came time to pass this rifle down to the Grandchildren they had trouble closing the bolt, so I had to push the shoulder back a little more just for the youngsters.
Today I have a neck size die added to the bench but most of my reloading today is done with a hickory stick
Good luck you have learned in this week what took many of us 20 years to learn.
Greg

[PCJim]

Gbro, I would venture that the younger generation on this forum have no clue what you meant by that hickory stick reference. Today, unfortunately, it and it's kissing cousins are despised by our evolving society and could get you a visit by the authorities and possibly a free night's stay on the government. And yet we wonder what IS happening to our society.....

[rdjordan]

I went to the gun smith this afternoon and he checked the headspace with a 'no go' guage and a 'go' guage. He said everything checks out fine. Also, he thinks that the chamber is just slightly oversized or out of round, but that it is completly safe and is not worth trying to fix.

So, I guess I am left with fire forming and only sizing my brass just enough. I am going to search for 'fire forming' and do a little studying on it to figure out what I need to do.

Anybody got any other suggestions?

[Selfdfenz]

I make the following comments more in the line of additional questions than advice.

Assuming you fire form the next batch of cases why wouldn't using a collet die to neck size only be one way to deal with this on the following reloads?

If you neck size only on the once fired factory cases you may have a solution perhaps?

Best

S-

[F. Guffey]

I am not a fan of small base dies, neck sizing dies, go, no and beyond gages, I am a fan of getting all the use I can out of a tool (moneys worth), with a standard die I can size a case with a small base. neck size a case and make go, no and beyond gages. As to the possibility of having a chamber that was not cut correctly, if a reamer has its own pilot the person piloting the reamer is the problem.



An opinion, fire forming will not work because the chamber has 'runout' if the gunsmith is correct in his guessing, to eliminate guessing he could have made a cast of the chamber or used or used long legged inside calipers to measure the chamber at 90 degree, 180 degree or as many degrees he chose to determine is the chamber was out of round, in doing so he would have been able to determine, in .001 thousands, the amount. Run out, eccentric, bulge whatever will happen at the same place every time, if the case with the bulge is not chambered to match the bulge, will it chamber, I would suggest marking the cases when chambering, after firing and reloading, index the case to assure the case is chambering the without moving the bulge. Reason: travel, if the case is moving out every time it is fired the wall of the chamber is getting hammered, this could cause the bulge to increase in size



I am a big fan of cutting down on case travel, again this is where I apply the 'LEAVER POLICY' once the case shoulder moves out to fit the chamber, I "LEAVER OUT". Neck sizing, I have no ideal why there is full length sizing or neck sizing with nothing in between. My dies and presses are variable because of the incline plain, the fact the threads are 14 per inch makes a degree wheel awkward so I use a feeler gage, I adjust the gap between the shell holder and bottom of the die, this helps because I know the head space of the chamber, I adjust the gap .001 less than head space, if nothing else this adjustment prevents the sizing process from moving the shoulder of the case back more than .001 under a go-gage.



Same page, I ask a question about chasing run out on another forum, they did not understand the question, the question went something like, "when chasing case run out, is the case standing or laying down" point being, if the case is laying down and rolled it will scribe to circles, one for the small diameter and the other will be the large diameter, the difference in the two diameters determine the amount of bulge, 'V' blocks, height gages, run out gages, I believe in getting the most out of each tool, it is not a matter of 'another tool', I would roll the cases first before firing and again after firing to determine the effect the chamber has on the case.



Neck sizing with a full length sizer has it's advantages. the part of the neck that is not sized aids in centering (supports) the case in the chamber, neck sizing can be progressive, as the amount of neck sizing increased, the die starts to size the body of the case, something like neck sizing with partial body sizing, remember, avoid moving the shoulder, this is accomplished by adjusting the die off of the shell holder, backing the die off 1/4 turn is .017 thousands + or -, use a dime if you do not have a feeler gage, feeler gage from Harbor tools $5.00, American made $11.00 + or - a few.





When I have purchased custom take off barrels I always ask 'WHY' was it removed, the answer is always, "it just didn't shoot good", some are free, some cost $10.00 and as much as $20.00, before I can use one I have to determine if there is a problem, biggest problem is chucking the reamer in the tail stock or tool post holder to cut the chamber, neither the barrel nor reamer can center or float, I tried to clean a 250/3000 chamber with a 257 Weatherby reamer, I wasted my time, the chamber would have required removing an additional .011 thousands, that would be .022 because of the 'two circle theory'. to shorten the barrel would have been a waste, without at least 24 inches of barrel, the 257 Weatherby has no advantage over the 25/06 or 257 Roberts AI.

F. Guffey

[blue dingo]

RDJ, I've been following this thread with great interest since I have a Savage rifle doing the same thing. It's a Savage 112 single action in 220 Swift. My spent brass looks just like Durham's and I'm pretty sure it has excessive headspace and also appears that the boltface is off axis with the chamber.
GOT, are you by any chance a Savage man? Guffy? I was thinking with that action all I had to do was get the barrel vice and action wrench and a "go" headspace gauge to set it back to minimum headspace tolerance. I was hoping that might square the chamber up with the boltface and eliminate (or reduce) the case stretching.
Anyhoo, like was said; it sure is nice to have all this knowledge and experience at yer fingertips. Keep us posted on that 270.
blue dingo

[GrumpyOldTex]

GOT, are you by any chance a Savage man? Guffy? I was thinking with that action all I had to do was get the barrel vice and action wrench and a "go" headspace gauge to set it back to minimum headspace tolerance.

Blue Dingo. Sorry I'm not a Savage Man. I know several people that have them and they like them and have had no problems. My 10 year old grandson has a Savage 22-250 that he can drive nails with as long as it's kept clean.
I would have a gunsmith check your rifle's headspace. Maybe the chamber is just oversize a little. Guffy is absolutely right.

As to the possibility of having a chamber that was not cut correctly, if a reamer has its own pilot the person piloting the reamer is the problem.

Fire Forming your brass and then neck sizing may not help the runout but it will improve case life. But fire forming should be done the very first time the the case is fired. When fire forming is done correctly, it moves the shoulder of the case forward to the chamber shoulder instead of moving the head of the case back against the bolt face.