25 Caliber Disco Slug Rifle

25 inch barrel:
.243 Bore .250 Groove 1:14 6 lands
Exhaust port .205 Dia

Modified valve:
.250 throat dia
.205 TP
Delrin valve stem w/ .315 OD
Valve stream lined to .110 and shorten to 1.010 from face to end of stem
Upgraded vale retaining screws to 10-32. Also added another 10-32 to front half of valve and added 8-32 to back half of valve for a total of 5 valve retaining screws.
Modified gauge port adapter

Rear cocking hammer assembly:
Total of 110 grams hammer weight
.300 Dia x .040 spring (.100 between each coil)

Standard Disco Trigger Group
Two screw mod

Breech modifications:
Bored bolt passage to .265 Dia
Extended bolt handle groove
Three set screws to retain barrel
Custom bolt and bolt handle

Specs with lighter hammer weight: (First Testing)
#1 810.9
#2 811.2
#3 805.7
#4 795.9
Fill PSI 2700 End PSI:1500
50 grn soft cast bullet sized to .249-.2495

* These #s were the first test #S Before upping the fill pressure and adding more hammer weight

Quick Spec. after adding hammer weight and upping fill pressure to 3000 PSI

50 grn soft cast sized to .2495 865 FPS

74 grn soft cast sized to .2495 692 FPS

74 grn soft cast sized to .251 632 FPS

A few pictures:


















Here are some targets I shot on my second day of test shooting. There was a pretty stiff cross wind this day. The first day of shooting I seemed to have a lot better grouping. So I hoping thats why my groups opened up, but Im out of bullet and Ill have to wait until I get more. I going up grade the trigger group to the Mrod trigger and play with sizing a bit. Try .251 and .250

50 YARDS








Thanks for lookin
Sean Stephens
workinmanVA

Not bad at all . Looks like you have more energy with the 50 grainers at this point . What barrel did you use ? Marvin

impressive results and the amount of work into it shows.

Congrats

from T.J's. T.J.'s sells T.O.W there barrels. Mike makes really nice barrels and I've used lots of them for my 32 cal Disco's and my 9mm DEEP HORIZON carbine. I just wish it had a little bigger groove, like .251. Something closer to the 25 cal LW barrels. I feel the twist rate is so so. 1 in 16 might be a little better but more testing will be required.
I don't know how the accurate the heavy 74 grn bullet will be at those speeds. Probably ok to 30 yards but woulb mostly Key Hole at further distances.
I would like to get a hold of some 40 grn RN and see how they preform. If you know any one casting them that could sell some I would really appreciate it.

Thank
Sean
workinmanVA

I have that barrel on my 25 caliber 201 . And there are more AR in the hands of shooters with TJ barrels than most people realize . I have thought about a 40 grainer my self . Have a old 50 grain mold I thought about making into a 40 grain but it is not in good enough shape to work with . And with LBT being the only option at $125.00 plus don't know if it will happen . Marvin

Sizing your bullets to in your 201 TJ barrel. Also what kind of accuracy are you getting.

So far .24975 with 12-15 bhn . Accuracy to 50 yards is 3 shots moa if I am doing my part . For the LW on my Condor I size to .24975 as well . Marvin

Sean,

1:14 is better twist rate for heavy bullets. I don't think that 74gr will keyhole... There is enough twist to retain it straight, although speed is little low.

Lighter than 50grains bullets, the 1:16 twist could be better. 50 grains go as well with both, 1:14 and 1:16.