This was posted on the SSM board when some hull failures came up with .410 load from Polywad.
"Posted on: Dec. 12 2007,9:05"
"I thought you might like to see Mr. Menefee's response to my letter, which he must have mailed to me the same day he received my letter. I really could not not have asked for a better, more responsible approach to the issue. The response is below. Cudos to Mr. Menefee and Polywad!!
Note the explanation - very interesting!! What I find odd is that this apparently happens with some guns and not others. Any thoughts on that?
Dec. 12, 2007
Dear Mr. Hartman:
Got your letter and samples of the .410s that melted the ends off.
Since shipping you the shells last summer we have made a powder change in the 3" .410 17 Gram Crak-R loads, because we found that in some guns, (and usually in these it was only occasionally), we would get some unsightly melting or tearing of the thin plastic hull.
This hull problem has nothing to do with chamber pressure, but everything to do with the friction caused by the plastic buffer beads that make nearly full shot column contact with the very thin walls of the hulls used.
The pressure curve, (how quickly we reach peak pressure) combined with the heat of combustion, contribute greatly to this.
(Finding a buffer that could even be used in our kraft cup "BioWad" 28 and .410 loads was an adventure in itself-going back several years. With some buffers, such as styrene, you will get a complete tear off of plastic hulls every time, right at the "buffer line" ! All that would eject from the gun would be the brass head!)
I first encountered this hull melting/tearing problem over 10 years ago, when we launched our first 28 gauge load, in the "Spred-R" configuration.
We had several 28 gauge guns here, and with the help of a very large US powder company, who backed up our own pressure testing, we made a load that was well within SAAMI specs for pressure, and was delightful in every way!
Except that the very first customer to buy a whole flat of them called me immediately with reports of losing an inch or more of the hulls once he had fired 6 or 7 shells in a row on a 5 Stand course. He sent me some and boy were they ugly!
We began testing in earnest to see if we could duplicate the problem. In my old 11-48 Remington Autoloader, (inherited from one of my Great Uncles--I used this gun growing up in Arizona, chasing after Gambel's Quail and shooting lots of Doves) we could fire 25 shells as fast as we could load the gun and pull the trigger--and never have even the slightest problem show up. Not once!
But---in another gun I had inherited, my Grandfather's AyA 53 E side by side...if we loaded and fired quickly, by the time we got to the 6th or 7th shell...we were creating shells like the customer had reported---really ugly with large parts of the hull missing!
The much cooler operating, long recoil, ventilated rib autoloader liked the shells. The solid rib double barrel didn't. Maybe chamber dimensions, forcing cone issues? Certainly heat dissipation was involved.
I talked to the powder manufacturer, and he had nothing to offer in the way of explanation. I called the late Don Zutz, who had been very interested in our Spred-R loads, and he helped a lot by mentioning that he knew that one of the "Big Three" US ammo manufacturers had had some .410s doing the same thing, and had cured it with a simple powder substitution.
Then, I called a man that became my greatest helper and booster in this business, Ted Curtis, who had worked for many US ammo manufacturers since 1939!
Ted simply said "Change from the Double Base powder you are using, to a Single Base, and you can probably solve this immediately." He was at that time, (in his late 70s or early 80's!) head of customer service for Accurate Arms Powder. He recommended Solo 1250 for the application. We made the change, and that was the end of the problem. Have been loading this load for 10 years now without another complaint or ever seeing it in our routine test firing."
There was more in the post, but you can see that with the 28 gauge, the shells worked in some guns and failed in others, until the powder was changed.
The issues Polywad had do not seem to match with the case with the Eley shell, unless the failures happened after the gun was heated by a few shots. Might be worth seeing if the Eley shells work w/o problems in some other guns.
Last edited by J. Hall; 01/22/08 02:14 PM.
