I'm getting my rifle back with a new barrel shortly. The problem is I have 150 rounds of brass loaded with the max load for the old barrel / chamber. These cases will most likly be .008" to .009" shorter at the shoulder than the new chamber (a local gun smith made the chamber under spec). Should I pull the bullets and reduce the powder charge or go ahead and shoot one. I've heard guys here and other places say to fire form brass, even when it means many thousenths expansion, with a full charge but I always use minimum.

shoot it - the guys that tell you to max loads are correct. minimum loads usually do not totally form the case

Shoot a few to make sure you don't have any problem. With the dimensions you're talking about most likely you'll get the TOP HAT effect with your primer slightly baking out and flatening. This by itself is no indication of excessive pressure.

First, tell us the caliber. The configuration of the brass (rimless bottleneck, belted magnum, rimmed, etc.) might make a difference in how you treat the "shorter" ammunition in the "longer" chamber.

It's a 7MM WSM, Without a belt, I was worried about the case "slapping back and forth" I once had the same situation with a .243 and it blew primers and wouldn't extract.

Okay, that does (or might) make a bit of difference compared to something like, say, a .25-06.

The short, thick, large diameter brass of the WSM case means that you've got quite a bit of brass to work with in the web/head/lower wall area. Assuming the worst, if all of the case stretching comes from the web area, then even .009" of extra headspace will likely not create a pressure ring that is thin enough to appreciably shorten case life. I would go ahead and shoot the "short" ammunition, despite the excessive headspace situation. After the first shot it will be formed to the chamber and so long as you do not push the shoulder back again you will probably never have any problem with the slightly thin spot created just in front of the web.

All of this assumes that the load, which you describe as "maximum" (whatever that subjective term might mean) is appropriately digested by your new barrel. Your "maximum" load may generate more pressure in your new barrel than in the old one, regardless of the chamber being "longer". Loading data for the WSM series tends to allow rather ambitious pressures to begin with (in the manufacturers' public relations effort to convince us that you can get just as much velocity from a smaller case as from a larger one.) I've seen lots of WSM factory loads that created sticky bolt lift and cratered primers, so I always advise extra caution when loading these rounds to "maximum" since the goalpost for "maximum" seems to be in some place other than where it is for more conventional rounds.

Curious how you use Std dies to load for a chamber that is .009 too short? Did you have room to bumb the shoulder or did you thin the shell holder?

Don't have the lengths a 7wsm go, nogo, and field guage but looking at the 308 the nogo is .004 longer than the go and the field (max safe headspace) is .008 longer than the go.

Big question will be exactly how much "slop" do you have. I would probably try up to .008-.009.

If it is CRF that will also help keep your case head next to the bolt and force expansion towards the front.

quote:

Originally posted by bedrok:
These cases will most likly be .008" to .009" shorter at the shoulder than the new chamber (a local gun smith made the chamber under spec). Should I pull the bullets and reduce the powder charge or go ahead and shoot one.

No - DO NOT just go shoot some!!! At best you will create Insipient Head Case Separations and at worst you could have a Ka-Boom!

Take a few(9-15) "other" Cases and properly Fire Form them. Then Develop the Load from below - as you always should do - while watching for Pressure Indicators, with the best being CHE & PRE.

Then if you can reach the Load you have in the 150 Cartridges, pull the Bullets until they will Jam-the-Lands(if they are inexpensive Bullets) and Fire Form them with that Load.

The real problem is that it is very rare for one Load to work well in all rifles chambered for the same Cartridge. They may shoot OK, or they may not. You have approximately 7/360 chances they will shoot OK, because the Barrel Harmonics will be different.

quote:

I've heard guys here and other places say to fire form brass, even when it means many thousenths expansion, with a full charge but I always use minimum.

There are a lot of ways to Fire Form, some work well and some don't.

Best of luck to you.

Excellent advice. I had planned to work up to the same charge in properly sized brass to check pressure signs but now I'm going to pull the bullets and reduce the charge to my usual fire forming charge (I make them from 300WSM)
Thanks for all the feed back.

Good for you.

quote:

Originally posted by bedrok:
Excellent advice. I had planned to work up to the same charge in properly sized brass to check pressure signs but now I'm going to pull the bullets and reduce the charge to my usual fire forming charge (I make them from 300WSM)
Thanks for all the feed back.

Check the new chamber vs the old chamber before you fire form. There are ways to push the shoulder forward a little if needed.
But then again your assumptions about chamber length differences may be wrong. The two chambers could be identical or the could be much more than .008 different in length.

quote:

Originally posted by Hot Core:

quote:

Originally posted by bedrok:
These cases will most likly be .008" to .009" shorter at the shoulder than the new chamber (a local gun smith made the chamber under spec). Should I pull the bullets and reduce the powder charge or go ahead and shoot one.

No - DO NOT just go shoot some!!! At best you will create Insipient Head Case Separations and at worst you could have a Ka-Boom!

Take a few(9-15) "other" Cases and properly Fire Form them. Then Develop the Load from below - as you always should do - while watching for Pressure Indicators, with the best being CHE & PRE.

Then if you can reach the Load you have in the 150 Cartridges, pull the Bullets until they will Jam-the-Lands(if they are inexpensive Bullets) and Fire Form them with that Load.

The real problem is that it is very rare for one Load to work well in all rifles chambered for the same Cartridge. They may shoot OK, or they may not. You have approximately 7/360 chances they will shoot OK, because the Barrel Harmonics will be different.

quote:

I've heard guys here and other places say to fire form brass, even when it means many thousenths expansion, with a full charge but I always use minimum.

There are a lot of ways to Fire Form, some work well and some don't.

Best of luck to you.

Gee! Will wonders never cease..

Seafire and Hot Core agree 100% on something here...

The question here is sort of like George Carlin's old skit on Motor Cycle helmets...

If you have a $10 head, feel free to buy a $10 helmet...

why mess with it..

I'd disassemble a couple, resize the brass to fit the chamber you have and then work up a load from that point..

disassembling a case is not that hard.. I do it all the time...

if your concern is how much time it will take, then do 10 or so at a time...and make it leisurely... don't be in a rush...

being in a rush at the load bench is when bad things end up happening..

How do you disassemble and then resize undersized brass to fit the chamber? Golly John ,be carefull who you go to bed with. roger

pull the bullets, reload with 90% powder charge, seat long, jamming the bullet into the lands. put the rim under the extractor before chambering.

Stonecreek got it right on. roger

quote:

Curious how you use Std dies to load for a chamber that is .009 too short? Did you have room to bumb the shoulder or did you thin the shell holder?

I had to shave a little off the shell holder then bump the shoulders on loaded rounds to fit the new chamber but the whole process was a waste of time. After all the money spent on it (he lapped the lugs, trued the face, etc.), it didn't shoot any better.

Sounds to me like you have a brass problem or there is something else wrong in the system like scope, bedding or just the wrong load...you didn't say just what your "accuracy" expectation is or what accuracy the rifle is actually producing.

I just built a 6-284 and have run through 100 107 MK's, 50 Horn 105 Amax and 6 different powders and 50 rounds of WW brass...without coming up with a good load.

This was with WW brass from a previous 6-284 all tuned up and shiny...I was about to send the barrel back to Shaw as defective...I've NEVER had this much trouble getting a rifle to settle down.

I finally ordered 40 Norma 6.5-284 rounds and bench prepped them today.

The first 5 rounds from a RL-25 load that was showing promise went into .5 x .5...that's better than ALL the other groups I've tried...3 on the inside top touching and two on the inside bottom touching...which could have been me or the bag shifting. The WW brass was spitting a few then bugholing a few so I was tossing the cases that weren't going into a 1" targedot...ended up tossing the whole lot of WW.

If a rifle with all the work you say was done, doesn't shoot then well then you need to take a look at the rest of the system and maybe yourself needing a "trigger tuneup" or work on your bag technique...we all need that sometimes.

YOu might take a look at just how LITTLE 0.008" is by opening up your calipers or mic. The amount you're talking about is pretty much SAAMI spec tolerance.

I've had rifles that have/had 0.020" headspace and all that happened was the cases died in about 3 reloads...you can get upwards of 0.015" headspace(or more) in old military boltguns AND new Remington Sendero's...ask me how I know.

You might try another brand of brass or buy the right size to see if it helps.

Luck

If you oil the case lightly it will fireform
without a stretch ring. Then adjust your sizer.

quote:

Originally posted by hawkins:
If you oil the case lightly it will fireform
without a stretch ring. Then adjust your sizer.

Can you explain this? You may be right but it seems 180 degrees out. roger

You can also run the brass into a die that is a little smaller in diameter and squeeze down the first half of the case. This will move the shoulder forward some. Then you resize to set the headspace with the normal FL die.

The oil keeps the case from sticking to the chamber walls so it will slide easier as it expands...supposedly. The thinner case walls toward the front of the case still are forced out against the chamber walls before the thicker portion of the walls and basically, theoretically, moves the ring farther forward rather than at the wall/base junction.

I tried doing it way in the distant past, or rather the gunsmith I was grunting for showed me how he wanted it done and stood back while I made the mess, fired the rounds, then cleaned the rifle, cases, workbench and myself...that was the last time I mucked about with that KRAP.

Sounds good tho'...supposedly.

But I don't see what all this pushing the shoulder forward has to do with it...the chamber is SHORTER than standard so just resizing it with a trimmed shell holder or sizing die SHOULD solve the problem.

I think this link is getting turned around somehow...or is it me?

Luck

quote:

If you oil the case lightly it will fireform
without a stretch ring. Then adjust your sizer.

Yes this is true but I do not recommend firing full power loads with undersized cases.

You must be careful about firing severely undersized brass in any chamber, clean, lubricated or what not.

The problem is peening. Too much case movement and the cartridge base will impart a shock loading to the bolt face. This can and has caused issues with locking lugs and receiver surfaces. Lubricated cases will just make this worse with full power loads.

However, if you went to a very reduced load, oiled the cases, I don’t think you will have a problem.

I lubed my 30-06 cases when fire forming them to 35 Whelen. I fired cast pistol bullets and used AA5744. My recollection was that velocities were less than 1700 fps in a 24” barrel.

Peening is another reason to use cartridge headspace gages and control your headspace. Too much and too little are both bad.

Since industry standard min and max is .006" with most cartridges, I do not believe that .006" of shoulder clearance will cause any peening problems, dry or lubed case.

[QUOTE]Originally posted by FOOBAR:
***

But I don't see what all this pushing the shoulder forward has to do with it...the chamber is SHORTER than standard so just resizing it with a trimmed shell holder or sizing die SHOULD solve the problem.

The Chamber is larger than the the ammo, if I understand the initial post. roger

quote:

The problem is peening. Too much case movement and the cartridge base will impart a shock loading to the bolt face. This can and has caused issues with locking lugs and receiver surfaces. Lubricated cases will just make this worse with full power loads.

I'm always amazed at the "information" that is shared here on this forum. Could you tell me the original source? THANKS!

Firstly, I am not sure what "peening" we are talking about here. I am assuming we are refering to the cumulative potential effect of firing undersized brass in a larger chamber, causing damage to the locking lugs.

With respect to leaving a film of oil on the round, the effect was explained to me many years ago by a very knowlegable reloader as follows:
If all things are right with the world, in the instant after the round is fired,(and we are talking micro seconds here) The case is driven forward and similtaneously expanded to fill any available chamber space. The case then pauses for a micro second, held tightly within the confines of the chamber by the pressure of the expanding powder gasses. As the bullet moves forward and pressure eases, the case relaxes and is driven backward against the bolt-face. If the case is not held for that all important micro second, the rearward impact can (over time) cause damage to the rear surfaces of the locking lugs. As I understand it, the "pause" of an unlubed case is one reason that cases strech at the case/web junction and an oiled case limits that damage potential. I would not oil and fire a fully loaded round as an ongoing practise, but for establishing a well fire-formed case (to be neck-sized thereafter) I think it is an acceptable practise.

How many loaded cases are we talking about here?

Didn't you say just 150?

Would all that screwing around to salvage too short cases really be worth it to you?

I'd consider just buying some new cases for my new barrel and going from there.

As to the old ones, well you could pull them down and save them just in case WSM cases ever transmogrify into unobtanium, or you could just unload them & throw them into the range pickup box (or your own version thereof) for sale to the local metals depot for recycling.

quote:

I'm always amazed at the "information" that is shared here on this forum. Could you tell me the original source? THANKS!

“Technical Notes, Small Arms Design”, Author: John G. Rocha , available from Armalite (800) 336-0184, stock number NA1085 $12.50 . Maybe be out of print, cannot find it on Amazon.com. This soft cover pamphlet is a copy of the course material handout to a firearms class taught at Rock Island in the 60’s.

quote:

If all things are right with the world, in the instant after the round is fired,(and we are talking micro seconds here) The case is driven forward and similtaneously expanded to fill any available chamber space. The case then pauses for a micro second, held tightly within the confines of the chamber by the pressure of the expanding powder gasses. As the bullet moves forward and pressure eases, the case relaxes and is driven backward against the bolt-face. If the case is not held for that all important micro second, the rearward impact can (over time) cause damage to the rear surfaces of the locking lugs. As I understand it, the "pause" of an unlubed case is one reason that cases strech at the case/web junction and an oiled case limits that damage potential.

Varmit Al’s structural analysis is the best model of the dynamics of combustion and case stretch I have seen to date. http://www.varmintal.com/a243z.htm

Yielding of Brass Case Walls in the Chamber http://www.thewellguidedbullet...allsintheChamber.pdf
and Steel Support for the Brass Cartridge Case by James A Boatright
http://www.thewellguidedbullet...assCartridgeCase.pdf

Mr. Boatrights contributions are excellent. Mr. Boatright also shows how P.O. Ackley was able to fire 30-30 Ackley improved cases in a lug less 30-30 action. After you find out how, recollect that ole P.O Ackley never fired a 30-06 Ackley Improved without lugs. The end result might not have supported his ideas about case taper reducing bolt thrust.

I don’t have a problem with using lubricated cases to fireform cases as long as the load is light.

The use of lubricated cases in automatic mechanisms is beyond living human memory. Examples of which are only fuzzy pictures in books or behind glass in museums. But there were fielded systems which used oilers.

quote:

“The lubricated case has been very popular and has been used amongt others by the Schwarloze machine gun and the Breda light machine gun in rifle calibre and the 20mm Oerlikon and Polsten”.

From Small Arms, Volume 6 of Brassey’s Land Warfare into the 21st Century, copyright 1999. Brassey’s UK, Authors D. F. Allsop and MA Toomey,


Let me add to this list the Japanese Type 11 Nambu. That gentlemen, is an oiler on the receiver top:








Oilers were messy, the soldier had to carry an oil bottle, spills attracted dirt. Once the German roller bolt was mated with the Russian fluted chamber the need for oilers disappeared. Oilers totally disappeared in post WW2 mechanisms.



I don’t recommend the use of greases and oils in bolt rifles. If the case is properly sized you should not experience case head separations.

I used lubricated cases in this M1a. I was able to take one set of LC cases 22 reloads without a single case head separation. “Recommended” case life is five reloads. I set up my dies with Wilson cartridge case headspace gages, I pushed my shoulders back from .003” to .006”, never more, and I never fired anything hotter than a 168/175 with 41.5 grains IMR 4895. The 175 gr load is hot, but I only fired it at long range. You can compare my load with data in reloading manuals and you can see that I am using mid range loads. (I consider them maximum for the M1a mechanism) This rifle is on its third barrel with the original bolt. I have not experienced any peening or receiver set back.



So, do I recommend lubricating cases for the general populace? No!, Heck no!

For people who do not use case gages to set up their dies, who think maximum loads are starting loads, use modern high pressure cartridges in antique actions, I don’t think those people ought to be reloading at all. There are too many threads from posters who have blown primers, case heads, damaged actions and themselves. Clint Fowler has seen so many damaged rifles he recommends that people only shoot factory ammunition. That is the safest recommendation.

If you are a darn fool, stay away from greases, oils, powder, primers, and reloading.

quote:

Would all that screwing around to salvage too short cases really be worth it to you?

Absolutely. This brass was made from fire forming Norma .300 WSM brass, turning the necks, doing the flash holes,primer pockets, etc. By comparison, I just pulled all the bullets, reduced the charge, and stuck 'em back in in about an hour and a half.

A final comment: I'm glad I reduced the charges.
The minimal loads in the short cases showed more primer flattenig (could be partly attributed to bounce, not just pressure) than 5.5 gr. more in properly head spaced rounds.