Floral foam. The wet stuff used dry about 3/16th" thick.

I use regular Styrofoam packing popcorn and have been for 30 years. The reason I like it better than the floral foam disc is that it fills the case but is still relatively weightless.  The reason why I like the filled case better is for the ignition uniformity.  If the case is filled the powder is always in the same position from shot to shot.  If the case is not filled but only capped the powder can assume different positions in the case from shot to shot.  If a wad of any type is used floral or otherwise and that wad is pushed down to the powder leaving space between the wad and the bullet base you stand the chance of ringing a chamber especially in vintage rifle with mild steel barrels.  I do at times also use a card wad on top of the Styrofoam filled case but not always but either way I always fill the case.

Many years ago there were several articles about chamber ringing caused by wads. Has this theory been debunked? I shoot old rifles with soft steel barrels so I haven’t used any wads, but would like to.
Mike

A friend of mine had been using kpock over powder in his 32-40 cpa. He recently did a test with and without and without the kpock accuracy was much improved. I use the dark green floral foam over the case mouth on the smaller capacity cases so I don't spill it in the action. I've tried with them without and cannot detect any  difference. 25 years ago many used to use the light blue  "sill sealer"  and it also worked well from what i remember. I think that's Is what everybody was using in their 32miller shorts on the west coast then.

In my opinion chamber ringing occurs when a wad of any type is seated to the powder of a non case filling load leaving a substantial space between the wad and the bullet base.
On ignition the light weight wad accelerates to a very high velocity before it strikes the bullet base. The high velocity impact causes a hydraulic affect of the bullet base obturating outward at the location of the bullet base of a chambered round.  The chamber ringing occurs at the location of the bullet base of a chambered round.  I do feel that it can happen in any modern steel barrel but likely happens more quickly in vintage mild steel barrels.  I am more than slightly embarrassed to say that I speak from experience.

This is gonna sound rather off the wall, but for purposes of constraining the powder in the bottom of the case has anybody ever considered pre-measured "capsules" of powder? Made of flimsy thin paper, cigarette paper soaked in saltpeter for example, as is done when making combustible cartridges for cap-and-ball revolvers that completely combust upon discharge. Dimensioned for a snug fit in the cartridge case and pushed down against the flash hole. I can see where it could work in a straight-walled case, not so well in a tapered or bottlenecked case. I can also see where it would be a royal PIA to make hundreds of them in preparation for a match.

Just a thought, as the morning coffee starts to kick in.

westerner wrote on May 23^rd, 2023 at 12:51am:

With breach seating of the bullet the bullet base is not in the chamber but in the barrel so if any ringing is taking place it is in the barrel not the chamber.  With fixed ammo the bullet base is in the chamber so when ringing occurs case extraction is affected in that as the ringing gets progressively worse extraction of fired cases get progressively more difficult because the case begins to bulge at the ring which in turn causes resistance to extraction. The deeper the ring the greater the resistance to extraction. 

In all the years I have been using Styrofoam wads I have never noted any degradation of accuracy over the long term.  The Styrofoam after being highly compressed from the internal case pressure is expelled from the barrel as dust.  Also something I watched for over the years is would it act as an abrasive while under such pressure but I have never noticed any abnormal barrel ware.  
Wax wads are not a new idea they have been in used for a long tome.  In some of his writing Harvey Donaldson spoke of adding rosin to his wax wads to help keep them in the case neck. I would think that rosin a substance used to add friction would be abrasive but Mr. Donaldson never mentioned any such affect from it.   At one time I was using granulated wax  used in candle making as a filler but I didnt like it as it added too much weight so did affect chamber pressures. It did work good and likely acted as an additional lube.  I like the Styrofoam packing popcorn because its virtually weightless so has little affect on chamber pressure, it fills the case so gives a more uniform powder ignition, and for as long as I have been using it has shown no negative affect, and its free.  I like free !

This was an interesting post on ringing the chamber on the cast bullets forum:
No wad is necessary. All it takes is a significant free airspace in the case and delayed ignition of the charge.

When I was at Camp Perry, OH in 1967 I witnessed DOZENS of M1 Garand rifles which were turned in for rebarreling, after having fired WCC Ball M2 ammunition loaded with WC852 powder (H380) in which a "ring" had formed adjacent the bullet base, partway up the chamber neck. One of the rifles was MINE! I also had a Winchester Model 70 with ringed barrel and the government paid for it to be returned to Winchester for rebarreling.

I have also examined DOZENS of Ruger No.1 single-shots which had been returned to Customer Service, mostly .45-70s, which had been ringed by shooters using wads pushed down against the powder. The service department had sectioned the barrels and had them mounted on the wall at the New Hampshire factory where they were and probably still are plain to see by students attending the police armorer's school. Some rifles had multiple rings corresponding to the bullet base location of various weight bullets they had tried.

Easily-ignited, relatively fast-burning pistol or shotgun powders, having NO deterrent coating, and which tolerate the free airspace in the case, such as Bullseye, Unique, PB, Universal, SR7625, Herco are not the problem.

Most prone to chamber ringing are heavily deterrent coated, spheroidal powders such as 296, H110, 680, 1680, H335, Ball C2, 748, H380, H450, etc. in which there is a high percentage of deterrent coating, and a small particle size in the base grain.

In pressure testing I did attempting to develop suitable .30-'06 loads to operate the M1 Garand, having correct breech and port pressures, using the government test barrel, I was not able to do so with 150-grain bullets using powders such as 748, H335, or Ball C2. I fact, I RINGED THE $5000 government combination breech-port pressure barrel! The results were EXACTLY the same as those observed with the WCC Ball M2 loaded with WC852.

My advice is that if a powder requires use of a filler in order to obtain acceptable ballistic uniformity, than IT IS NOT SUITABLE for those particular conditions of loading.

For reduced rifle charges, lightly deterred, perforated flake and extruded tubular powders such as #2400, 5744, RL7, 4227, 4198 will give best results. Of these Alliant #2400 is the only one which in my experience, performs normally at loading densities below 50% of case capacity. 5744, RL7, 4227 and 4198 should not be loaded at less than 50% of available case capacity. Extruded powders slower than RL7 or 4198 should not be loaded at less than 70% of case capacity. The Hodgdon 75% rule is sound!

For full charge loads, choose a powder in which a safe charge occupies not less than 80% of the powder space and in which velocity standard deviations of a 10-shot sample fired with the powder uniformly positioned using a "SAAMI roll" do not exceed 1% of the sample average. The military procedure is more severe and consists of 5 rounds fired "base tap" and five rounds fired " nose tap" in the sample.

I punch out wads from the water pipe insulation.
I plug the case mouth to prevent any chance of ringing my barrel.
One Alberta Schutzen Guild member ringed his RKS stainless steel barrel at the base of his seated bullet by placing floral foam directly down on the H108 powder.
He now slices off wads from window foam backer rod and plugs his case mouth to prevent ringing of his new barrel.

  I'm with calledflyer, a sharp knife.

A couple years ago, I was doing a vinyl siding job on a house
of mine. 
Used Fan Fold foam House Wrap under the siding .
When I got the "urge" to go with breech seating, I messed with pipe insulation, and the floral foam.
And then it hit me to try a couple pieces of left over House Wrap. It is +- 0.225" thick. I just peel the very thin film off it and then cookie cut with my loaded cases. I do like to have the case mouths inside chamfered to make better cuts on the foam to plug the case mouths.
Works great, it is also polystyrene like the floral foam, but
is a bit more dense foam and is not brittle and crumbly like the floral foam. No indication of any bad residue in the barrels.
beltfed/arnie

talking about hijacking a serious thread.....
beltfed/arnie

I believe his reference to the percentages of case volume all apply to the absence of any type of case filler.  In my opinion when a weightless CASE FILLER !!! is used those percentages do not apply.
Again it may be helpful to look at a shot shell where the powder charge occupies a very small percentage of the case volume. Since in a shot shell the projectile is 100% internal withing the case the actual case volume might be best measured from the bottom of the shot cup to the top of the case head.  Still it is quite a large volume because most shot ammo is in much  larger calibers that what we generally discuss here..

Red Cent wrote on Jun 4^th, 2023 at 6:48pm:


I thought that a flat laying powder charge was one of the causes of the secondary explosion effect that causes mayhem to rifles

And what happened to all the posts....did the anti humour bandits strike again 
Gumpy 

Shame about the posts, 
The S.E.E. is thought to be when the flame rolls over the top of the powder causing a massive area to ignite at once and cause a pressure spike instead of the ignition travelling through to powder column in a controlled manner.
Gumpy

I was pissed (at myself) while dealing with a powder location problem of my own.  While pulling bullets on some loads I was planning on taking to a match that were too hot for my 30 Wesson Ballard, I found 50 of the 100 rounds with a powder location problem.  The powder was still in the powder bottle and not in any of the cases. Not sure a primer only load would be accurate at 200 yds.   

Jack

Where is Biggi.  She needs to photoshop a squirrel over the finger.  (That should confuse a lot of people)

I only used very thin foam wads.  1/16" or so.  I did try Daves pipe insulation once but that is more suited for pre-charged cases.  Mine was a 32 Miller Short High Wall.  The foam was used to keep from dumping the powder into the action.  This was that barrel and action from Chuck's estate that had the large nut on the barrel end.  I still have the barrel and the action has the 28 barrel on it now.

Red Cent, Charlie Dell proved that with a flat powder face (like shot straight up in the air) and a decent air gap you don't need a wad to ring the chamber.