carbon fouling on spent cases.

[maver]

Hi guys


I have a question: On Sunday I shot my Full Length Sized Lapua 6.5x55 brass that was trimmed back to the same length as the shortest case in the 200 or so cases I have. (This brass was only fired once in another rifle hence my FLS (Full Length Sizing it).
So my dilemma is this; All the brass was treated the same through preparation from cleaning to FLS, but I wanted to experiment with neck turning so I decided on 3 methods and 10 cases selected at random in each trial:

1. I took of brass all the way down to about 1mm / 1.5mm from the shoulder.

2. I turned only the high spots all the way down to where the shoulder meets the neck

3. I did not neck turn the third set so they were left as FLS only.

I have rounds from last year I used to foul the barrel and set the scope for 100M. I shot these and the brass came out clean as a whistle when ejected.

Now to my test subjects; Each round fired no matter what category it belonged to above the brass came out filthy covered in burnt powder / carbon and my bolt face was black also covered in burnt powder / carbon. This was not the case with the rounds I had loaded from last year which were only ever neck sized only after their first firing that I used to sight in the rifle with just previous to firing my test loads and have been used about 10 or more times.

I had thought OK this is due to the brass being FLS and not fire formed as yet.

So Sunday evening I cleaned up the fired brass from the 3 categories and Monday morning reloaded the same Fire Formed brass and off I set to test my loads once more. Hoping now that the cases would not be coming out covered in burnt powder and perhaps the loads a little more accurate.

Unfortunately I had similar results to the previous day. Brass was covered in burnt powder the belt of the case head was filthy black also and the bolt face filthy black. I had to keep taking out my bolt after the 3 shot (so called groups) and wipe the bolt clean.

Now do you think this could be due to the cases being trimmed a little to short or the case neck not expanding enough to seal the chamber (even so there was cases used that had not been neck turned at all but still caused a lot of burnt powder /carbon to blow back into the bolt face).

So any thoughts are welcome?

[SHOOTALL]

was it a light load ? maybe not enough to expand the case to seal the chamber fast enough ?

[maver]

shootall,

it was an almost max load for the 6.5x55 lapua scenar 139g HPBT.  It was 45gn of vhitavouri N160. The max load in their manual is 45.1gn.

[Dave in WV]

Did you clean the resizing lube off of the cases?

[maver]

Dave,

When I neck size I never use lube.  I find that my Lee neck size die doesn't require me to use it.

[hoghunting]

 I know your load is close to max, but it sure seems it is not hot enough to expand the brass to seal the chamber. Take an old case and a Lapua case and fill them both with water. Weigh the water, and the Lapua probably has a larger capacity. If it does, slowly increase your charge and look for any pressure signs.

[maver]

hog

that sounds like a recipe for disaster if i shoot a load larger that the manual recommends although i take it that most manufacturers will have some room for expansion built into their published loads...

the only old cases i have are lapua...and these cases i have are now once fired from another rifle lapua that have been full length sized and trimmed to all the same length....

DO YOU think that annealing the case neck and shoulder would make a difference even so its only once and twice shot brass....

[Mikey]

maver:  I think you trimmed your necks too far back and get blowby as a result.  Take a once fired case, full length size it, load it and see if it soils your action.  If not then you should consider that you shortened the cases too much.  Why did you trim back to the length of the shortest case? 

The brass from last year - was it trimmed and was it trimmed as far back as this brass? What rifle are you shooting?  Match barrel/custom chamber? 

[maver]

Mikey

I trimmed them all the same length so that i got the same uniformity in all the brass and also when chamfering the flash hole inside the case.

I did not trim much off the necks it was maybe 1mm or so.  All my once fired cases are FLS and trimmed.

Brass from 2009 was not trimmed as far back as I only got the wilson trimmer this year.  I always used the hand held neck trimmer from Lee just to ensure the cases did not exceed maximum length.

Im shooting the steyr manlicher pro hunter II 6.5x55 and its just an off the shelf hunting rifle barrel.

[Mikey]

maver:  I'm sorry buddy but I stillthink you trimmed the brass back too far.  I would suggest trying some non-trimmed brass and see if you get the same results. 

If this is a 'off-the-shelf' rifle, even though it is a Steyr and a quality made rifle, and there is no real need to trim back the cases although I can understand your quest for uniformity, I would not trim them back that far. 

If, let's say, you load your bullets to just kiss the rifling even after trimming back the necks, that would leave a 1-1.5mm distance between the case mouth and the end of the chamber or rifling which would give you enough room for a lot of blowback, I believe.  As the bullet is moved out of the case and engages the rifling, the burning powder has two places to go instead of just one and with the trimmed cases the neck may have not yet expanded to seal the chamber before the gases and soot blow by -just a guess, but I still think you should try some un-trimmed cases to see if you still have the problem. 

If your rifle is a hunter, it should work about the same as my old Husky M38 in 6.5 - that is, it takes just about anything you can chamber in 6.5x55 and still shoot more accurately than I can.  I think trimming back the cases may have 'dun-ya'.......

[S.B.]

I'll assume you're turning the necks to improve accuracy? With military barrels(again I assume this is what you've got on your rifle), don't think this is either nessisary or useful. Turning necks is usually done on extremely tight chamber match rifles, to improve accuracy? The question begs to be asked, what do you expect to gain with this proceedure in a factory standard barrel? By the way, you leave out several important facts about this, how much did you turn off the necks, what barrel are you shooting these in(match, military, factory), powder charge you loaded in these brass, how much was trimmed off the brass before turning, how short was your shortest case of this lot? You did successfully create excess chamber space to alow gases to flow back around the neck of the turned cases but, why? I would suspect all these turned brass will split in the neck area, soon?
Steve

[maver]

Mikey

I have tried brass that was not trimmed back stuff i have from last year that has been shot almost 10 times or so and it works fine...it comes out pretty clean.  But I have none from this lot that has not been trimmed.  I didnt believe that the amount of brass i trimmed of would have 'dun me' but it may well have.

I was just trying my quest for tight groups at 100M etc as I use this gun for big bore silhouettes and wanted tight groups and uniformity to guarantee that the mechanics were good so all that would be troubled would be my mind...:-)

Steve
I though I had mentioned the load in used in the first post but its Vhitavouri N160 45gn and 44gn firing a 139 lapua scenar HPBT the brass is all lapua as this is all I use.

I only neck turned 10 cases all the way to the shoulder removing brass all the way down and in the next batch i only took of the high spots and in the third batch i did not neck turn any cases...but all soot up the bolt and chamber...so the trimming looks to be a culprit although i am amazed at how little was taken off and the causes of it...

do you think if i run an already trimmed case back through the FLS die will it lengthen the case so that it may seal the chamber in time when fired...

 

[Mikey]

I don't think fl sizing will stretch the case 1-1.5mm.  I would try a batch of new brass and just load it.  Is there any reason you can't save $ by purchasing Remington or Winchester brass; that Lapua brass has to be pretty costly.  I would think that if your chamber is tolerant of length, as it should be for a hunting rifle that might see any number of different manufactured ammo,  case length uniformity beyond manufacturer's tolerances may be of little benefit, and you are shooting a off the shelf rifle.

[maver]

Mikey,

I am only reloading for 2 years now, and I got my first lot of brass although mixed as it is by purchasing Lapua ammo, 20 rounds per box.  It was costly but I had not discovered reloading at that time as it was my first centre fire rifle and still is.

I do not mind paying the extra few euro for Lapua brass as I know their tolerances in manufacturing are second to none.

I was just trying to find out if my of the shelf rifle could shoot that thrill seeking 1 shot group at 100M / 200M.

 

[Mikey]

maver:  the Steyr Pro-Hunter is a fine rifle and with the European penchant for 6.5mm bores I seriously doubt you will be disappointed.

As for ammo - if you are reloading the Lapua it is probably made to European specifications and your reloading equipment and components (primers especially) are probably made to handle Euro spec components.  With this in mind I would suggest you get yourself some Sellier and Bellot 6.5x55 ammo and use those cases or just go with US made components.

The sole reason I do not reload for my 6.5x55 Husky M38 is because it is so darned accurate. This rifle will give me snake-eyes from the bench at 150m and should I ever want to go try a 500m metallic silhouette course for rifle that is the one I would use and use it with S&B ammo.  If I was going to reload the S&B cases I would get the proper sized primers and reload the Euro made brass.  I may have to do that anyhow because I still have a bunch of 6.5mm S&B empties.....

I reload the 8mm and I made the mistake of tossing the S&B 8mm cases I had because I didn't have any Euro-component sized equipment - I could have obtained it easily but instead opted for Remington 8mm brass and US made large rifle primers - all good though as I put 10 rounds into one hole from the bench at 100m with my Husky 8. 

I hear ya on having to buy ammo just to get the brass..  Good luck.....

[maver]

Mikey

I may get to fire my rifle this weekend over a chronograph as I have 3 rounds of the trimmed cases left (the ones that soot up) and about 7 rounds of the non trimmed 2009 lot that I made up back then.

All Lapua cases with CCI large rifle primers BUT NOT exactly the same powder charge the three (sooty) case loads are filled with Vhitavouri N160 45gn. with 139g HPBT and my clean 2009 rounds have 44gn of same powder and bullet.

I will expect the (sooty) rounds 45gn powder to give an extra few fps compared to the 2009 rounds 44gn so that will be some indication that the load is hot enough to expand the case neck.  IF ITS NOT THE case then there may be a problem with my RCBS chargemaster powder dispenser and scales, or perhaps the bullet is not seated tight enough for pressure to build up inside case?

[Mikey]

maver:  I would shoot the non trimmed brass first just to enjoy the rifle; then shoot the trimmed brass.

I would not hesitate to believe that either powder charge, 44 or 45 gns of Vit N160, in the 6.5 Swede is sufficient to fireform the case to your chamber.

I would expect the trimmed rounds to give you less velocity - you are loosing pressure with all the blowback allowed by the trimmed cases and that should drop your velocity a bit.

[maver]

mikey

your theory of velocity drop is something i hadnt thought of.  i hope i get to take the few shots today as its world cup time and we have a house opposite range as we are a .22 range. I cant be makin to much noise there.

[Mikey]

maver:  let us know how it goes.  My thought is that you have 21-1.5mm of empty space that will allow your gases to expand before the bullet begins taking to the rifling and that should cost you both pressure and velocity; but it will be interesting to find out what actually happens.

[maver]

didnt get to shoot  today so will try tomorrow. Here is a scenario i was given. As the cases are now that bit shorter and i am seating the bullet to the same depth then perhaps the pressure is not getting time to build in the case as there is less bullet to be gripped by the neck therefore bullet is released sooner and case does not get to expand in time.

[usherj]

Hi Maver,

I shoot and reload the same caliber in a couple M96s and a Tikka T3. For all the rifles I only neck size and have had no problems in hunting or target shooting, and I believe that is due to the nice concentric chambers in those Scandinavian rifles. I have had some sooting issues in one M96, even when using faster powder and the Lee factory (taper) crimp. Most rounds would soot only on the neck like you want, but some would carbon the shoulder?? Identical load. For rifles when you can't seat the bullet close to the rifling or when you have light neck tension, the lee crimp is supposed to help provide some initial resistance to help with more consistent ignition. My advice is to forget the FLS, that should resolve your issue and drastically increase your case life (12 or more loadings is not unusual). Don't sweat the trimming, as long as you keep the length at or below 2.155". In my Tikka I had alot of blow back with light H414 loads developed by someone else. Now I use 46.2g of RL22 behind the 140 Nosler Partition with CCI BR-2 primers. Before I adjusted the OAL I got 3/4 to 7/8" groups. Seating the bullet .005" off the lands shrunk the 3 shot groups to 3/8"! Not too shabby for a light hunting rifle. That bullet has lots of contact with the neck and is seated close, so no need for crimp. Also, I only use the lee hand trimmer and check with the calipers. If you are compelled to FL resize, try backing off the die a bit to only partially bump back the shoulder (all you need for a bolt gun is .001"). This process does still resize the body, so if your chamber is a bit oversize or deep, you must keep an eye on potential head separation from working the brass that way. It really is a wonderful cartridge. I hope this is of some help to you.

[maver]

Usherj

Myself and a friend were coming to the conclusion at the weekend that the shoulder may have been pushed back to far and not sealing the chamber fully and this is where the soot is getting an opening to blow back too.

Do you know of any methods that will allow me to reshape the shoulder, other than another firing which i suspect wont work unless i have more of a pressure build up in the case through crimping or seating the bullet deeper???

[usherj]

The Nosler #5 manual (p 254) has a recommended procedure of fire forming std 280 Rem brass into a 280 Rem Ackley Improved chamber. They recommend using a light load of relatively fast powder, with the bullet seated well into the rifling. If you have any N150 that would be great, otherwise the N160 should work. Use your books minimum charge for that powder and bullet with the bullet seated to contact plus .002", so you will engage the rifling well. At least you aren't working without a net, since it is recommended practice. Check with Mo's in Brookfield,CT to see if he has a gauge for that caliber. With it you can accurately measure the headspace of fire brass and then set your die so you only bump the shoulder back .001" and don't over resize. If you don't have a gauge you are guessing. Good luck

[maver]

usher

im not familiar with mo's of CT. Do you have a website url or number for them.  im based in ireland.

I doubt very much my bullet will even reach the lands as it is a hunting rifle.  I have tried this in the past and the seating i have at the moment is the best i can do without the scenar 139g bullet falling out of the case.

[usherj]

Mo Defina at Master Class Sports
166 Pocono Rd
Brookfield, CT 06804 USA
Tel (203) 775-1013

Mo is a high master class shooter who builds and works on rifles for many competitive shooters in this region, and has great prices on equipment and accessories. He has no website, but you get him on the phone and he is very knowledgeable and helpful.

The Lee factory crimp can help make up for a long throat by providing the consistent initial resistance needed for uniform ignition. Good luck

[Mikey]

maver:  no matter what you try, you are still firing 6.5x535-.54mm cases in a 55mm chamber.  I think you should just bite the bullet and get some new cases.

[maver]

Usher - thanks for the info - but i am not sure of what I am to ask Mo if I call him.

Mikey - I will definitely consider new cases - once i give the few options i have been given a go.

To Do list

seat the bullet deeper in the case
lee factory crimp bullet
Tighter neck size on case
lastly up the charge by .1 or .2 of a grain.

[usherj]

Maver,

Explain your problem to him and ask if he has a Mo's gauge for 6.5x55. It is similar to the Wilson case length gauge, but better because you can get an actual headspace measurement on your fired brass and then set your FL die to size it the minimum amount needed to push the shoulder back .001", and not excessively resize. If the rifle is used, not a bad idea to get it checked out. Factory ammo is by necessity undersized to fit all chambers, and the blowback condition rarely results. If your headspace is excessive, a good gunsmith will be able to set the barrel back and recut the chamber if needed.

[maver]

hi usher.

The rifle is approx 2:5 years old. I am the only owner. I would guess there has been perhaps 3000 rounds down the barrel.

I will give mo a call on monday and see what we can do.

Thanks for all your help and suggestions so far.