More Info:
http://www.frfrogspad.com/miscellh.htm#make blank
"Q. How can I make blank ammunition for my rifle.
A. Blank ammunition for manually operated rifles (not semi autos) is not difficult to make. Before going any further on this topic two warnings.
First, NEVER, NEVER, NEVER take the powder from GI .30-06 blanks to use in other calibers. The EC powder used in those blanks was also used as a grenade filler and pressures can get out of hand VERY quickly.
Second, do not attempt to use these home made blanks with blank firing adapters on self loading firearms. Such blanks require a very careful tuning of the load and you can get in trouble very fast if the hole in the blank adapter is not correct.
Third, please review the the question on the dangers of blank ammunition on Page 1 of these Q&A pages before using blank ammunition.
The smokeless powders used for military blank ammunition such as EC, SR4990, HPC-13, WC-814, WC-818 and similar are not available on the commercial market.
For 308 / .30-06 and other similar capacity cartridges try 12-20 gr of either RED DOT or SR 4759, (the GI M82 long neck 7.62 mm blank has been loaded with 17.5 gr of SR4759 and the "short neck" rosette crimp M192 blank with 21.5 gr of SR4759) or 9 to 10 gr Unique (work up from the lower charge to get the desired results). You can close the case mouth with a small piece of kapock or quilters batting and a drop of shellac or you can use a special rosette crimp die available on special order from RCBS, Hornady (#544590), and CH Tool & Die/4D (under their "specialty dies" heading--they have a wide assortment of blank making dies). Use a drop of shellac to seal the hole. The rosette crimp helps with feeding.
For .223 blanks try 5 to 8 gr of Red Dot, with a rosette crimp sealed with a little varnish.
If you want "big" blanks you can make .50 BMG blanks by using 44.5 gr of Hi-Skor 700X, and close the mouth with a rosette crimp or use a card wad glued in place. 12 gauge blanks are easily made using 50 gr of FFG black powder or Pyrodex topped with a 1/2" Styrofoam wad (cut using a brass 10 gauge case) that is seated firmly. Crimp the case as normally done.
Some folks have reported getting good results by using a sharpened case to punch out pieces of 1/8" felt as a closure wad which are then sealed in place with a drop of shellac and a light roll crimp. (You can also try using a mild roll crimp or even using a small caliber die of the same basic case size (such as a .243 for the .308 or .270 for the .30-06) to provide a reduction in case mouth size.) Never use any hard material for the closure wad as you will have a projectile capable of inflecting a serious wound.
Pistol caliber blanks can be made using a very fast powder like Norma R-1, Vihta Vuori N310, or Hodgdon Titewad, or Red Dot. Start with about 2 gr with a card or foam wad cut from a sheet of thin craft foam and work up to the desired noise level, but don't exceed the maximum charge listed for a light bullet. You may have to enlarge the flash hole to prevent primer setback.
If you need specialized blank cartridges in quantity for organizational or theatrical use try contacting one of the surplus ammunition distributors or one of the major commercial blank ammo producers such as the following
http://www.joeswansonsmotionpictureblanks.com
http://www.duffysguns.com/BlankAmmo.htm
http://www.hbci.com/~nartron/prod12.html
** A SPECIAL CASE **
If you need reliable .30-06 blanks for honor guard use in the M1 Garand using the GI issue blank firing adapter you can safely use 8.5 gr to 10 gr of Unique with the CCI #34 (military hard cup) primer. Use the charge that gives the desired noise level and functions the rifle. Use a rosette crimp die to close the case mouth and seal with a drop of lacquer. DO NOT USE ANY WADDING!!!!! Note that the rifles need to be clean and lubricated and the gas port in the barrel needs to be centered in the opening of the gas cylinder for things to function."