Jim: There are no good Substitute powders. You have several gun clubs around Dallas/Ft.Worth, and you should have no problem finding other ML rifle shooters.
Use and shoot Black Powder. You can order it through the mail from Powder Inc, or Graf & Sons. See the Links section on the index here. Both will ship small quantities of 5-10 lbs. of powder per shipment. A usual case weights 25 lbs, and you do save money buying it by a case. The secret is to find a few other shooters to go together to split the approx. $275.00 cost for the 25 lb order. They will mix powders per order, too. That means you can buy some 2,3,4 and even 1Fg powder in whatever combination you desire, provided the total is 25 lbs. Same when ordering as little as 5 lbs. The HAZ MAT fee is $20.00 per shipment, so you do better by ordering more powder than less, spreading the fee over more pounds of powder. Ex. With a 5 lb. order the Haz Mat fee costs you an extra $4.00 per pound. At 25 lbs. that same fee is now under a dollar per pound($.80). With a 50 lb. order, that is down to $.40 ! And, with the case orders, the two dealers pay the shipping charges. I believe the last comment on this forum from someone who just ordered powder was it cost him about $11.50 per pound delivered to his door. Compare that to $30.00 per pound for Triple 7!