doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Pressure Variance Between Fibre and Plastic Wads

Washboarding the barrel metal in one or various degrees. I don't think I've actually seen it or at at least never noticed it. So I'm not so sure it's relevent to todays guns and steels. Though for thin walled S&S's maybe so.

Thanks. I was just reading through an older thread on the subject. It is news to me.

I'll send you a PM on 2" loads.

On many a gun that has had the barrels reamed I have clearly seen what might be described as washboarding. I don't notice any difference in felt recoil or fps from my loads compared to other guns without washboarding.

I am wondering show important is a gas seal when using fibre wads? I have never used them and always use a lubed fibre wad. I know my fps are always around 1200 fps but no idea what they might be using a gas seal. I also note that I have never been able to pick up an intact fibre wad after firing a load. They are usually split in many pieces or disintegrated.

I cut the cups off of some WAA style wads and used them over the powder with a fiber cushion. There was pretty strong increases in velocity and pressure. But these were 2" loads in 3" chambers, so that data may not transfer particularly well.

I will share this from my own observations and findings, all empirical and no lab testing. I did as the OP mentioned, substituting some assorted 'fiber' wads from earlier times using load data that was published as quite safe in the original CFAA 12 ga. hulls [LUP was the pressure units used specified on some and psi on others and some were just published by the powder or wad maker(s) w/o pressure data] and quickly noticed that the hull length was stretched considerably after firing and also that the crimp folds were ironed out and disappeared! Had similar results w/several types of card & fiber wads, inclusive of Alcan's in several iterations, Federal, Winchester, &c. The worst offender was the Ljutic Mono Wads, which surprised me.

I also had similar results in some plastic 28 ga. hulls, most notably Remington's with the Riefenhouser(sp?) hulls that I had a lot of at that time, though it would tear the hull's mouth off altogether at times.

After giving it some consideration, I concluded that the pressures had to be much higher w/those fiber wads than plastic ones and in looking a bit at the fired hulls and cutting numbers of them apart, it is apparent that the inside of a previously fired plastic hull is considerably rougher than it was when new and smooth, so further concluded that the fiber wad is being compressed into that 'rough' surface, perhaps even before it gets moving good and that's what causes the hulls stretching and probably is also increasing pressures dramatically, though I never sent any to be tested. What I did was to stop the practice and use tested plastic wads in plastic hulls and load the fiber wads only in paper hulls. Paper hulls tubes remain smooth on their insides after firing and only experience burn through at the juncture with the brass after some firings. Have not experienced a problem of stretched hulls or ironed out crimps since.

Doubt it would happen with using a fiber/card wad in a new plastic hull for one-time use. Never noticed a fired RST card wad round loaded in a plastic hull to have stretched after firing. Others here could speak to that issue when using other brands of ammunition loaded in plastic hulls w/card &/or fiber wads.
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Different FWIW, issue encountered several years ago was with some older AA12 wads that had become brittle in their original packaging. The wad fingers would snap off if tested by hand. I was scoring very poorly with them even tho they 'sounded' normal. Went to the grease plate and discovered that they were apparently shattering and turning into molten plastic by the burning powder that was blown up into the shot and leaving the bbl. as a semi-solid projectile, much like the old classic 'whistler' one sometimes got from a paper hull loaded too many times w/with too many pin holes in it and everything from the brass head forward went out the bbl. usually making a whistling noise when it did so. Solution to that issue is to put any wads whose petals are brittle in the trash and do not load them.

I can corroborate that. My experience was with the WAAF114 and a Winchester Ball Powder. The wads were about 10 years old and looked and felt fine. They left melted plastic in the bore. I've used Claybuster and Remington wads twice that age with no such issues.

I don't load fiber wads as I have no application for them. This thread is however interesting.

I wonder how much the crush section or lack thereof plays a part. Seems like gas sealing might be only a part of it.

I don't know the validity or accuracy of testing 50-60 years ago but I have been using the MEC data and old reloading manuals from that period for all my Fiber Wad loads ever since.

It has been shown time and time again that fiber wads produce less pressure and more often less velocity with the same powder charge than their plastic counterparts. From years of testing and experience, I generally shoot plastic wads thru all of my guns including black powder loads because they simply pattern and perform better. Yes, there is some plastic fouling with black powder but that can be cleaned up with no problem.

I too have had old plastic wads to become brittle and "rotten", when in the original plastic bags. No particular brand is suspect.

With fiber wads I was able to obtain consistent velocities due to seating the wads with at least 60 lbs. pressure. I concluded that it wasn't powder compaction, but the downward pressure on the wad causing it to bulge against the walls of the hull effecting a more consistent seal against the gases bypassing the wad. I also used honey bee wax to coat one of two nitro cards used in my recipe for 2" 12 ga. loads. While the the velocities were consistent for my purposes they weren't as consistent as plastic wads. The old rule of thumb regarding switching from plastic to fiber was that 10-15% more powder was needed to offset the relative inefficiency of fiber compared with plastic. Gil