Nice article in Nov/Dec 77 American Handgunner on Thompson Center Contender

[ohland]

http://www.americanhandgunner.com/1977issues/AHND77.pdf

THE THOMPSONICENTER CONTENDER
By Massad Ayoob
GENISIS OF A PISTOL .................................................. .....40
INTERVIEW: WARREN CENTER ............................................... 42
CONTENDING WITH THE CONTENDER ........................................ 46
THE COLLECTIBLE CONTENDER ..............................................51

THE T/C INSTA-SIGHT ...........................................J.. D. Jones 53

[MT Gianni]

Great articles in that. THe opening one on 2.7 gr Bullseye is still being debated.

[BD2]

+1. Awsome articles.

[35remington]

The idea that powder laying horizontally in the case sees more of said powder ignited at one time than in other orientations can be disproved by anyone with a chronograph. The current term for it is "flashover detonation" and it has no credibility whatever.

[Artful]

The idea that powder laying horizontally in the case sees more of said powder ignited at one time than in other orientations can be disproved by anyone with a chronograph. The current term for it is "flashover detonation" and it has no credibility whatever.

Gee, I used a chronograph and proved that powder position can make a difference....


Trailboss experiment 3/15/2007 - Part Duex
I've wanted to load some subsonic ammo for my .308's, todays experiments concentrated on my Imbel FAL with it's 21 inch barrel. We had some more rounds to try out. These loads are not recommended and is only for information purposes. This is our day... :)

All ammo loaded in Remington 308 case's w/ 150 grain Hornady Flat Base spirepoint bullets fired by CCI 250 magnum primers. (a shorter bullet than the last bullets experimented with http://www.quarterbore.net/forums/images/smilies/wink.gif )

Weather 87 deg F - sunny, not much breeze... AAC Cyclone can

Last time we had taken Suputin's advise and cleaned and lubed
between groups of powder trials [http://members.shaw.ca/cronhelm/DevelopSubsonic.html],
today we wanted to see if we could use the barrel without special preperation (which is how it would mostly likely be in the field).

13 grains of Trailboss
All fed from the magazine...
Can off - Grenade gas setting 1251, 1332
Can ON - Grenade gas setting 1309, 1367, 1340
Can ON - Semi-Auto Setting 1243, 1336, 1317

12.8 grains of Trailboss
All Fed from the Magazine
Can off - Grenade gas setting 1181, 1202
Can ON - Grenade gas setting 1097, 1313, 1334, 1313, 1338, 1333

12.6 grains of Trailboss
All fed from the Magazine
Can off - Grenade gas setting 1163, 1199, 1089
Can ON - Grenade gas setting 1142, 1277, 1293, 1158, 1317

Now we had noticed an unsettling velocity gap that had developed in some of the strings and we decided to take a side branch to see why there could be several hundred feet per second spread in these carefully weighed powder charges.... deduced that the angle that the charge was in the cartridge case was playing a part in the velocity changes so to test that theory, that we tried loading ammo into the rifle in different ways.

The TILT UP method involves putting a cartridge in the chamber and then tapping the gun to settle the charge to the rear of the case then gently lowering the muzzle to the rifle rest and firing the charge.

The other method of loading the charged cartridges, was done by laying the cartridge on top of the magazine leaving the rifle facing the target and hitting the bolt release, which will distribute the powder more or less evenly over the bottom of the case as the BOLT Rammed it home.

first we just wanted to see if the up tilt was going to produce a difference

12.4 Grains of Trailboss
Can off - Grenade gas Setting - up 929.2 , up 1079, up 1146
Can ON - Grenade gas setting - up 929.0, up 1016,
Can ON - Grenade gas setting - bolt 1324, bolt 1311,
Can ON - Grenade gas setting - up 1115

12.2 Grains of Trailboss
Can off - Grenade gas setting - up 986.2, up 1120, up 1148, up 992.2
Can ON - Grenade gas setting - up 951.9, up 1117, up 1185, up 1145

12.0 Grains of Trailboss
Can off - Grenade gas setting - up 956.1, up 960.0
Can ON - Grenade gas setting - up 1087, up 1141
Can ON - Grenade gas setting - bolt 1282, bolt 1281, bolt 1268, bolt 1247

11.8 Grains of Trailboss
Can off - Grenade gas setting - up 950.6, up 1170
Can ON - Grenade gas setting - up 1024, up 1147
Can ON - Grenade gas setting - bolt 1261, bolt 1220, bolt 1232, bolt 1208

All holes in the paper target exhibited roundness with no tipping evident, but several times it was noticed a wide swing between impact area's with can on vs off and again between tilted and bolt loading but I would expect this with velocity veriations at these slower velocities.

Now keep in mind these where all individually weighed powder charges
so they are as listed to with accuracy of the balance beam scale.

Conclusions:
While lubing will help with subsonic loads, I'm not sure it's required.

Not even the hottest load attempted to cycle the action.

Evidently Trailboss is sensative to powder position (in fact moving the powder to the rear of the case seems to lower the velocity by several hundred feet per second with the same powder charge)

While case loading density is about 1/2 the case, I'm not yet sold that Trailboss is the best choice for subsonic loading.

I've never explored "flashover detonation" and I'm not planning to but I doubt I'd just dismiss other's experience without more research into it- myself.

[M-Tecs]

Thanks for the link. Blast from the past. It was fun to read it again.

[35remington]

Artful, try it with the mentioned Bullseye and get back to me. No such effect as Cooper postulated exists with the blamed Bullseye.

Before it was warned against, I tried Trailboss with filler and got lower velocities than without. The difference according to a Hodgdon tech was less free propagation of the flame through the powder with filler. In my very extensive testing Trailboss is the only powder I have noted that suffered a velocity loss with filler.

This exains your results pretty well. What it does not do is set a benchmark for all other powders.

I have always, always noted lower velocities with powders strung horizontally as opposed to near the flash hole. So much for flashover detonation theory. It is absolutely invalid for the powders frequently claimed to "detonate."

The problem with those supposing "flashover detonation" is indeed lack of experience.....on their part. Such suppositions have invariably never involved any investigative testing that I have ever heard of.

I extensively test for this in multiple calibers. Always have. I dismiss nothing......I debunked it via a great deal of deliberate powder positioning, from fast to slow.

[Artful]

I have not seen bullseye for sale in 3 years :veryconfu

[35remington]

I just picked some up last week, an 8 pounder. Yeah, I didn't hesitate, because I hadn't seen any in 3 years either. Actually three and a half.