Reloading 410 slugs, 90gr and 127gr slugs with attached UHMW-polyethylene bases
Working to make them more accurate
WARNING: The information described on this page is for amusement only! Actually doing any of the following is dangerous to life and limb. The data on this page has NOT been tested in an instrumented test barrel and thus I have no real idea how much pressure the loads are producing. These loads could damage or destroy your firearm and possible even damage or kill yourself.

YOU HAVE BEEN WARNED!
Testing performance of attached base

The setup
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The slugs with bases: Left: UHMW Polyethylene Base, Center: 127gr Foster Slug, Right: 90gr Foster Slug
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Conditions

Conditions: Warm mid 70's, moderate humindity, and a nice breeze. All the testing was done at 25 yards from a shooting bag on a bench. The chronograph was setup 10 ft in front of the muzzle. All the slugs were fired through a Steven 38B with a 3-inch chamber 22.5 inch barrel cylinder bore.

Slug Construction


Load construction for 90gr slug with attached base

Note the above picture does not show the powder charge or PTFE tape.
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Load construction for 127gr slug with attached base

Note the above picture does not show the powder charge or PTFE tape.
(click to enlarge)
Slug Construction

Both loads were constructed the same with the difference being the powder charge and the slug. The base is made from Ultra-High Molecular Weight Polyethylene. The base is 1/2" long with 1/8 inside the hollow base of the slug. The exposed part is 0.375 diameter except the bottom 1/8" that is full bore (0.410") in diameter. A little hot-melt glue is used to hold the slug and base together. The slug is then wrapped in PTFE tape (sold as a thread seal for plumbing) I wrapped the slugs untill they were almost 0.420" in diameter. I found a thicker yellow PTFE tape that is used for residential gas lines that seemed to work better than the regular white PTFE tape. The basic construction was as follows:
  • Fiochi 2.5 inch primed Hulls
  • Powder charge was pored in.
  • Half of a Stump wad was used as a gas seal
  • 1 - 3/8" felt was uses as a cushion
  • Then slug with attached base and wrapped in PTFE
  • Finished with a roll crimp
90gr attached base slug

90gr attached base slug with 13.9gr Herco, 5-shot group at 25 yards, Group Size: 3.9 inch
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Load and Velocity data

Load 1: 90gr attached base slug
Charge: 13.9 gr Herco
Velocity Data:
Low Velocity: 1835fps
Hight Velocity: 1930fps
Average Velocity: 1885fps
average velocity from two earlier test with same powder charge 1960fps 1930fps Extreme Spreed: 94.53
Std. Deviation: 46.29

Group Size: 3.8inch

The last time I shot this load with just the PTFE tape and no attached base it shot a 3.3 inch group. In this test I did notice that the two shots that went high where two shots that were outliers as far as velocity goes. The three close together shots were also the three shots with nearly the same velocity. The two higher shots both had velocity noticible above the other three. If I throw the two high velocity shots out of the group it results in a 3-shot group size of 1.3 inch. I think that this load can work very well if I can be very carefull to get consistent powder charges and consistent crimps. I would also note that these were shot after testing 30rds of the heavy weight 163gr slugs and the barrel was horribly leaded up. I think that in a clean barrel this load is going to be very accurate.
127gr attached base slug

127 gr attached base slug, 11.4gr Herco, 5-shot group at 25 yards, Group Size: 2.6 inch
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Load and Velocity data

Load 1: 127 gr attached base slug
Charge: 11.4 gr Herco
Velocity Data:
Low Velocity: 1511fps
Hight Velocity: 1586fps
Average Velocity: 1555fps
average velocity from two earlier test with same powder charge 1597fps 1543fps Extreme Spreed: 75.65
Std. Deviation: 29.29

Group Size: 2.6inch

The last time I tested this slug with just the PTFE tape and no attached base it shot a 4-shot 4.8 inch group. This is almost half that size and 5-shots. I am really please with this load. Again I would point out that these were shot after 30rds of the 163gr slugs and the barrel was horribly leaded up. I would like to work the velocity up a little be more. At present they are generating about 681ft-lbs. If I could get that to about 800ft-lbs which would be about 1680fps I think I would hunt deer with them from the previous terminal test the slug at 800ft-lbs would penetrate sufficently for deer hunting.
Conclusions: I am very pleased with the performance of the attached base for the foster slugs. I am already making more and some for the heavy weight slugs. I will definitly being using this construction methode for other new loads.


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