drilling out flash holes?

[RU shooter]

I have seen mention of this subject before about drilling out the flash hole when using light loads so something or other dosent happen to the case shoulder . I was wondering at what load levels should I be concerned about this? I mostly shoot ligh loads in my 7.5 swiss and 308 win. and 7.62 Russian ,and my normal loadings are 155-185 gr. boolits and usually 7-9 grs of bullseye or W231 or 9-10 grs of Unique. I dont know what vel. these are moving at I dont have a chrono, I never much cared about it as long as the accuracy was good Is there a velocity minimum that dictates opening up the flash hole? TIA.......................RU

[tommag]

The onlly time I recall flash-hole drilling being called for was when using the rubber bullets with no powder for indoor practice.

[Larry Gibson]

You don't mention which Russian but with rimmed cases there is no need to drill the flash hole (except perhaps for my second reason mentioned below). On cases that headspace on the shoulder when using the really light loads (cats sneeze, gallery or squib loads) the force of the primer explosian drives the case forward and will set the shoulder back. This may give missfires because of eventual headspace problems with some rifles. How many times it takes (fired with these light loads) for this to happen depends on several variables but it does happen. Drilling the flash holes prevents this.

Another reason I use cases with drilled flash holes for these light loads of very fast burning powder is that in many instances the powder occupies a very small amount of the case volume. Depending on where and how the powder is positioned may cause some erratic ignition. With the drilled flash hole the primer flame gets out into the case as fast as possible and probable is more effeicient at covering the entire case volume. In other words it ignites the powder right now. I won't shoot squib, gallery or plinking loads with these light charges without using FHR (Flash Hole Reamed) cases.

For LR pockets I most often use the largest flash hole feasable and yet still have a step for the primer anvil to rest on. That is with a #28 drill.

I don't shoot the Swiss but in the .308 11 gr of Unique under the 311-155 pushes 1550 fps out of a 26" barrel M70. With 6.5 gr Bullseye 311291 runs 1100 fps and with 2.8 gr Bullseye the TL314-90-SWC runs 828 fps.

I use cases with FHR in several cartridges. I have also carefully worked up to my normal loads (1700-1950 fps range) in the .308, '06 and 8x57 using FHR cases with 4895 powder and medium to heavy bullets with a dacron filler. I have had absolutely no indication of any excessive pressure. I actually recently loaded up 150 such loads in the 8x57 (after testing and working up to this load) using the recent GB mould (190 gr) with 30 gr of milsurp 4895 with dacron filler. These averaged 1750 fps out of a scoped Yugo 24 and shot 5 into 1.1" at 100 yards.

Larry Gibson

[mooman76]

I drilled flashholes on some 6.5x55 once fired brass. That was only to get it up to standards. The hole was so small my decapping pin would get stuck in it and sometimes pull the pin out!

[Jim]

I used to play a bad guy in a cowboy acting group out in Texas. We drilled the flash holes in our .45 Colt blank loads to keep the primers from backing out. Recently, I did some testing on load development for "gluelits" and found it neccessary to drill the flash holes out for the same reason. Powderless loads for rubber bullets require it also.

[RU shooter]

Thanks all So I guess my "light" loads arent that light after all. I thought they were more in the neighborhood of 900-1100fps. Good thing those boolits dont realize they need checks yet! So in a nut shell I'm good at lets say 7 grs of powder and up with normal size flash hole?

Also on another note my data for cast boolits Ive been using I have gotten from one of those one caliber all loads books and its for the 308 ,Can I assume correctly that all of the not max. loads will be fine in the calibers I listed above? and I am assuming the vel. I actually am getting will be alittle less than what is listed do to the larger case volume in the 54R ,and 7.5. Thanks again in advance

[Larry Gibson]

Your assumptions would probably be correct.

Larry Gibson