What causes this as? 257 STW 65gr IMR7828
I'm sure excessive head space is not the problem as the chamber is new. (less then 15 rounds) The other powders I was trying worked fine then this popped up!
Iím kind of at a loss hereÖ..
Starting at 65 gr using RL-25, Retumbo and IMR-7828 I have worked my way up to 84 grains of powder and the denting problem has gone away, there is sill sign of powder escaping 1/3rd of the way up the casing and Iím running into pressure signs above 82gr. All this began when I switched from a 115gr bullet to a 100gr I switched back to 115 using 75gr and of course no denting but there is still signs of powder 1/3 of the way up the casing. The necks on casings while using 100gr bullet simply are not expanding! Even when they donít dent there is still no expansion I have even turned the necks and still nothing???
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November 22, 2007, 08:33 PM
You are getting that when you fire the round? DIIK (darned if I know).
That looks like the bullet seating die is seated too far into the press by several threads to me.
I also am confused about your saying that the case neck is not expanding with the 100 gr bullets. It sounds like you are trying to expand your case neck ??? What? Why? If you shoot hot loads they will expand a little and then need to be resized, but this is not desirable.
Your best bet is to STOP and get someone that has been reloading for a while to come over and look at your set up, or take all of your info to a local reloader that has been doing it for a while. 84gr of 7828 sounds too high also. I have a 7mm STW that tops out in that powder at 82gr according to the reloading manual. Don't blow yourself or your gun up.
November 22, 2007, 08:39 PM
As a guess, I suspect the powder is too slow and you're getting erratic burn. That's the reason going to the heavier bullets helped. Looks like the neck isn't sealing and the gases are coming back around the case. Are those powders recommended for that application?
I load for a 25-06 using bullets in the 100 grain range and use 4350. Having that much powder available to push that small a bullet will most likely complicate things. How many times do you see a powder charge that weighs more than the bullet? Almost never.
Honestly, a case dented like that would scare the crap out of me. I'd think you're a good candidate for a ringed chamber or barrel. The primer pops the bullet out of the case and starts the burn. The volume has expanded enough that the powder burns too slow (slow powder with lots of coating). Enough of the powder then burns to build enough heat/pressure to start the bullet moving again.
November 22, 2007, 09:41 PM
I think Redneck is correct. The fact you are getting powder a third of the way down the case supports his theory. What are your indications of over pressure? A lot of times backed out primers and flattened primers are an indication of under pressure.
November 22, 2007, 09:47 PM
I have no idea, but if I were to guess I'd say your 65gr of IMR 7828 is way UNDER pressure. I have found little data on the 257 STW, but what I have found shows your charge of 7828 should be in the high 70's and low to mid 80's. A under charged round of very slow powder can be a very dangerous thing.
November 23, 2007, 12:37 AM
You said head space was not the problem. That is not what I see.
If gas is getting around that case, it is a head space problem.
The next thing you will find is a very loud squeak when the round goes off. This was a lucky one. Make sure that bullet is not touching the rifling.
Check the chronograph. If you are not measuring the head space correctly this is what will happen. Neck sizing will help. Check your expander ball to see that it is not oversized for that bullet too. May want to take a look at that chamber also.
That shoulder looks way too rounded and is not even close to the correct head space.
One other thing that can happen, is too much lube when sizing may get a small dent started at the edge of the shoulder and go un-noticed. When she goes bang you will notice.
And Steve is right,,,, Under PSI is very dangerous.
November 23, 2007, 03:12 AM
Welcome to the forum!
We're glad you are seeking hekp with this problem before something serious happens.
Now could you help me??
I"ve been searching for 10 minutes and cannot find any loads for thsi cart.
May I ask,for my own info,where you got these loads?
November 23, 2007, 10:45 AM
This is one of the few places I have found data on 257 STW along with the guy who built the rifle http://www.reloadersnest.com/frontpage.asp?CaliberID=239. I once had a small amount of powder blow back in my face while trying an experimental .223 load ever since then all my experimental loads are fired mechanically with no danger to myself or others. With that being said I would still hate to blow up a $5,000 rifle!
November 23, 2007, 11:03 AM
"You said head space was not the problem. That is not what I see.
If gas is getting around that case, it is a head space problem. "
Could just as easily be too LOW a pressure.
Without enough pressure the case mouth will NOT make a good seal and pressure can leak back to produce a case that looks exactly as pictured.
Low pressures can also result in primers pushed part way out of the pocket.
Unless the size of the cartridge EXACTLY matches the chamber headspace, the case is pushed forward by the primer being struck.
The case than expands and grips the chamber walls.
The pressure pushes the primer back against the breech face, partly out of the pocket.
When the pressure gets high enough the case stretches and forces the case head back against the breech face and the primer is again seated into the pocket (though flush now instead of the usual few thousandths below flush).
If the pressure is not high enough to stretch the case, the primer that was pushed out remains out of the pocket slightly.
A good seal may also not occur and powder gases can leak back past the neck of the case and dent the shoulder.
Rounded shoulders would be another indicator of low pressure.
It occurs also when fire forming cases and the pressure is not high enough to force the brass tightly against the entire chamber.
Firing a brand new case is a 'fire forming' step.
The case is sized to fit ANY gun of the same caliber, and the shoulders are often slightly rounder from the case forming dies.
After the first firing the case matches the individual chamber of the gun it was fired in (minus the very slight 'spring back' of the brass that aids extraction.
If it was after sizing, but before any other step it could be case lube, but that is a LOT of lube.
Lube dents are usually a lot smaller.
November 23, 2007, 11:41 AM
I bought some once/twice fired 5.56 that had been trimmed for another guys gun, trimmed too far for my AR-15, but I used them anyway. On the trimmed cases less than ~ 1.73" or so, I saw neck damage like that after being fired, other in-spec cases were fine, with the exact same load.
That's one possibility, a trimming issue.
November 23, 2007, 11:50 AM
I have seen the same type of dent in a case before but it was for a completly different reason BUT it does bring me back to thinking about a possible headspace problem. When I have seen that dent, it was caused during the sizing process.....too much case lube and for some reason that part of the case seems to be the weakest and dents there. If you have a headspace problem and pressure is moving backwards in the chamber the dented cases makes sense. BE VERY CAREFUL with this and have the gun checked out by a compentent gunsmight.
November 23, 2007, 01:39 PM
Unfortunately, Your data source "Reloaders Nest" has been shut down. I had a chance to check out their 257 STW data before they crashed. Most of the loads were 84 to 85gr of IMR 7828 with 85 and 100gr bullets. The only 115gr load listed was 78gr of IMR 7828. According to Reloaders Nest data your 65gr of IMR 7828 is dangerously low. That is almost 25% below published data.
You kinda answered your own question when to said that the dents went away when you worked up to "Proper" load levels. Loading very low levels of slow powder can be more deadly than an over pressure load. It's a really good idea to keep your loads within safe Min and Max levels for your own safety. You are lucky all you did was damage your cases.
November 23, 2007, 07:17 PM
birdbustr - if you look very closely at the photo I think you will see a faint ripple in the case where the neck intersects the shoulder. The shoulder looks too round to me too. That further supports your assertion that he has the die screwed too far into the press.
I use both Retumbo and IMR7828 for my 25-06 so I am familiar with the powders. For both I use CCI200 primers. Of the two, Retumbo is the slower powder and when I use it with 100 grain bullets I will get mild blackening around the neck but nothing along the side of the case indicating blowback because of improper expansion during ignition. I get no blackening shooting Retumbo with 117 or 120 grain bullets indicating the added weight allows more complete ignition. I neck size only and the bullets don't have a canilure but I still use a mild crimp for consistency. I use Retumbo because it is scary accurate in my Ruger #1V.
IMR7828 is also a very slow powder but it is noticibly quicker in my 25-06 loads. The raport is much sharper and I have never had any blackening of any kind using it. It's also very accurate in my Ruger.
November 23, 2007, 07:35 PM
It has nothing at all to do with headspace, die adjustment, or anything of that nature.
That can only be caused by a low pressure load of very slow powder.
Gas and possibly unburned powder granules are getting in between the case & chamber wall before the case can expand to seal it off.
Perhaps more neck tension, or even a crimp will be needed to get the pressure up enough to expand the case before the bullet releases from the case.
At any rate, do something different and stop shooting that combo before you get blowed up!
If a case totally collapses out past the rear of the chamber you going to have a catastrophic failure.
It has nothing at all to do with headspace, die adjustment, or anything of that nature.
That can only be caused by a low pressure load of very slow powder.
November 23, 2007, 11:28 PM
Iím not going to blow myself up as I said before the gun is fired mechanically but I would still hate to blow up a $5,000 rifle. I switched to faster burring powders and the problem is still the same case dent donít go away until max load is reached and I for one do not feel comfortable shooting at max load. I think I will just forget the 100gr and go back to 115 or maybe I will try 110, my seating die is not a crimp style or I would try that...
November 24, 2007, 10:34 AM
If the 115gr bullets work better for you that's great, but please understand that it is not the bullet weight that is giving you problems. It is the relationship between your powder charge and your bullet weight.
You are seriously under charged with 65gr of IMR 7828. You need to get your loads up were they are safe. You will not "Blow Up Your Rifle" with a max charge of powder. You may see signs of over pressure like blown primer, cratered primer, sticky bolt lift, loose primer pockets etc. If you find you are showing one or more of these signs then just back off a grain or two until they go away. Not 20 grains like your 65gr load.
You will however blow up your rifle if you keep loading rounds that are Well below Min charge. It is called "Detonation" and it will make tooth picks out of your rifle and severely injure or kill you and everyone around you. Here is a good discussion on the subject of detonation. Please read it. I would hate for you to damage your rifle and yourself.
I know that data is hard to come by for the 257 STW. If I were you I would call or email all of the powder and bullet manufactures and ask for data help. Hopefully some of them can help you out.
Remember, a "Min" charge is just as important as a "Max" charge when using slow powders.
Good Luck and Be Safe!
November 24, 2007, 04:11 PM
65gr is where I started! I'm up to 81 grains before the case denting goes away but that is at the cost of pressure signs on the casing and I for one donít like to shoot with pressure signs. Backing off the powder charge even 1 grain brings me back to dented casings thatís why Iím going to forget 100gr bullets for now and shoot something I feel comfortable with
November 24, 2007, 05:32 PM
Be careful with detonation, not right burn rate caused by small charges of powder being to far from the ignition source(primers). the air space will cause the powder to explode instaed of burn. If loading small powder charges are necessary, it can be done by using afiller on top of charge to keep powder next to ignition source. talk to someone you trust before going any farther ...
November 24, 2007, 05:36 PM
+1 to what rcmodel said
November 24, 2007, 06:06 PM
I still don't buy the reduced load "detonation" theory.
There is only so much energy in a small charge of smokeless power.
And it has been proven time and again that a small charge of smokeless powder cannot support a detonation wave across it's surface.
If it could, you could easily make a powerful bomb out of a 1 pound can of rifle powder & a blasting cap, and that is just not possible.
I believe what happens is, in fact, a bore obstruction right in front of the chamber.
Suppose the primer fires off, and the reduced load doesn't get a clean burn started.
But by then, the bullet has been moved out of the case, and into the rifling, but there is still not enough pressure to keep it moving.
So it stops, stuck in the rifling by friction.
But by then, the burn progresses, the pressure builds up rapidly, and is confronted by a bullet stuck in the bore right in front of the chamber.
It's not an over-bore reduced load "detonation" of the powder, it is a bore obstruction right in front of the chamber!
It's the same scenario which caused the case collapse that started this thread, only carried one step further because of a stuck bullet right in front of the chamber.
I'm up to 81 grains before the case denting goes away but that is at the cost of pressure signs on the casing and I for one donít like to shoot with pressure signs.
What type of pressure signs are you experiencing?
November 25, 2007, 01:53 AM
DITTO what rcmodel and Steve4102 are telling you.
I'm doing something very similar to what you are doing.
I'm loading for a .257wbymag, and forming my brass from OFB 7mmRemMag brass.
After forming the "ogee" or double radius shoulder, I have to fireform them to the chamber, and in some instances a slight ring is formed just behind the case shoulder on the case body. The formed cases are sized just sufficiently to easily close to bolt on, but still require the "filling out" of the shoulder similar to what you are experiencing. The ring behind the neck will only "dissappear" when loads are within 7-5% of Max. or roughly equivalent to factory loads.
(yes the cases are ~0.050" short, but it's not an issue. When brass is so long it has to be trimmed, it's time to throw it away !!!!!!)
I'm using mostly WC-860 powder that is from pulled down .50BMG brass. It has a small (less than 1 ppt -part per thousand- of something simular to H50BMG) the WC-860 has a burning rate essentially that of H870 and is somewhat slower burning than 7828. If you can find some of this, you should get it, as it's perfect for that "flame-thrower" you have !!!
(bought mine for $5.00/lb from Widners back in August. Bought a lot of it !! I also have a .300RUM thats it the best and most accurate powder I've used in it.)
I'm using 75gr (temp under 70deg F.) and 74.0deg over 70deg.F with a 115-117gr bullet. I found this out by developing my loads when temps were over 100deg this past summer. I rechrono'd the loads and found that they had lost ~150fps, so I had to "bump" them up a little for hunting season. Especially with bullets 110gr and lighter. Very similar to what you are experiencing.
I Saw a very similar pattern to what I'm seeing with your loads when using the aforementioned loads and 100gr bullets. I'm now back to using H4350 for the 100gr bullets as it's very accurate and gets essentially factory ballistics and velocity as well. I started with the starting load for the 115-120gr bullets and worked upward, till I reached the predicted max load of 80.0gr. The case will only hold 82.0g, and bullets can only be seated to depth over 80.0 before bullet deformation occurs, hence 80 is the max as that's all the cases will hold......... Velocity was decent at ~3,400fps and accuracy was excellent. However, drop the temps to ~65deg and velocities dropped to 3,180-3,220fps. Not bad, but not good for 80gr of powder, when my .257Robt's will get 3,100fps with 45-46gr of H4350 !!!!
So, the 100gr bullets are "out" with anything slower than RL-25 or Retumbo, which I have, but haven't had time to "play with" meaning, work up the loads. But with the 1,000 Hornady 100gr "Blems" I got from MidwayUSA, who knows ????? anyway, whats wrong with a 100gr bullet a 3,500fps anyhow ??
Back to the "problem".
Note that the powder charge of H4350 for my somewhat smaller case (approx.15%) is close to what you're having problems with in a significantly larger case and slower burning powder.
I'll repeat the question that Steve4102 asked, as he's in the right direction. Some "pressure signs" can also be signs of "low pressure" and with Newly formed brass being fireformed, also indicate excessive headspace (which in a way it is..) and "excessive pressure" which is actually low-pressure with an accelerated case "impacting" the bolt face causing burnishing and flattened primers. A clear sign that it's LOW pressure is that the primer is flattened, but not cratered. Cratered firing pin holes can be excessive pressure, or an undersized firing pin/over sized pin hole. (got a tack driving .223Rem that does that with ANY load........). Also, the blow-back is a sure sign of low pressures. I see that a LOT with the .45Colt in my 24"bbl Winny M94 and "Cowboy" loads.
Be more specific, or better yet more detailed pictures so we can help..........
Are the dents you're showing in the picture from sizing/forming the cases? If so, they're from excessive lube in the die. If from firing, it's the gas backing up under the case before the pressure rises sufficiently to obturate the case to the chamber. And as others have stated, if the case gets enough backpressure under the case, it can cause case failure and a lot of HOT GAS in your face, and everywhere else it vents out from the action. In an extreame situation it can case a pressure excursion from the bullet accelerating and then stopping in the bore, and then being essentially an obstructed bore causing the "alledged" detonation, which as Steve4102 has been shown not to be detonation of the powder column but the reaction of the firearm from a second pressure "spike" or WAVE as it appears on an ocillograph or computer printout. This then results in the firearm "exploding" due to a lack of a sufficient vent.... ie: the open bore from an accelerating bullet and bullet exiting the bore. After all, the firearm is only a single stroke heat engine, with the piston leaving the bore. Ever experienced a crankshaft failure in an internal combustion engine ???? I have; a crankshaft siezed on a Continental O300D aircraft engine I was operating. Not a pretty sight! and a LOT more expensive than a $5,000.00 rifle letting go.
Especially if you're at 5,000' and in the clouds as I was.......
BTDT, but fortunately no scars to prove it !!!!!
Do be carefull out there !!!
WAR EAGLE !!!!! 17-10, 6 in a row and counting.....
AU ALUMNI- CLASS OF '78
November 25, 2007, 03:42 PM
Well sounds like you got good advice from every angle. Heat up that load. Get the head space right and the lube off the case, and your problem should go away. Low PSI can raise some real problems. Which in turn cause other problems. If head space was not the starting issue, it rapidly became one.
Low PSI w/ no gas seal and maybe the start of a dent from lube, ?????
None of us were there. $5000.00 or $500.00 wont matter if that round backs up much harder on you. If these guys are loading for this round and having no issues, I would get their source's. And can the one you have been using.
Good luck Be safe.
November 28, 2007, 06:37 PM
Hey Huntinco, haven't heard from you in awhile. Hope you are getting that 257 STW on track. Anyhow, RN is up and running again, temporarily. If I were you I would slip on over there and copy all of their 257 STW data before they go down again.