Load Data for 170gr Cast - .40 S&W

[TPK]

I'm trying some 170gr cast bullets in my Glock and am not having a great deal of success so I am looking for suggestions.

I'm using Universal powder and can't find it referenced anywhere in relation to .40 S&W and 170gr cast bullets. Most sites I hit for info listed two or three other powders. I checked a burn rate chart and Universal powder is between the fastest and second fastest of the three powders listed. So it's not the slowest listed and not the fastest listed. Looking at it that way, I decided to start my loads using the info for the powder that was a little faster than the Universal powder I have. I loaded 5 of each, 4.7 grn up to 5.1 grn in 0.1 grn increments. 4.9 grns seemed to be the only load that didn't tumble or otherwise shoot all the over the place. Was that just "luck" or ..? can 0.1 make that dramatic a change? Perhaps it's the factory barrel that is an issue? Any way, I've got 1000 of these cast bullets and would like to use them so any info would be appreciated. I'll load up 20 or so of the 4.9gr load and see if I can repeat the success to start with and if not, then I guess I'll start loading down from 4.7gr in 0.1 grn increments and see how that works.

 

[polaris]

lead bullet loads

Please read this...

The manufacturer Glock advises against using lead bullets (meaning bullets not covered by a copper jacket) in their polygonally rifled barrels, which has led to a widespread belief that polygonal rifling is not compatible with lead bullets. Noted firearms expert and barrel maker, the late Gale McMillan, has also commented that lead bullets and polygonal rifling are not a good mix. However, since neither H&K nor Kahr recommend against lead bullets in their polygonal rifled barrels, it is probable that there is an additional factor involved in Glock's warning. One explanation is that Glock barrels have a fairly sharp transition between the chamber and the rifling, and this area is prone to lead buildup if lead bullets are used. This buildup may result in failures to fully return to battery, allowing the gun to fire with the case not fully supported by the chamber, leading to a potentially dangerous case failure. The other explanation is that Glock's barrels may be more prone than normal to leading, which is the buildup of lead in the bore that happens in nearly all firearms firing high velocity lead bullets. This lead buildup must be cleaned out regularly, or the barrel can become constricted and result in higher than normal pressures.

 

[TPK]

Yes, I was aware of this (read the post on "Glock Talk") but thanks for the post anyway. I will continue to try and shoot lead out of my Glock, I'll just be a little more wary and clean the barrel more often. I'll try to slug the barrel and see what the calipers say and then check the cast bullets I'm trying to use. On another thread on Glock Talk it was indicated that the Glock factory barrels like the lead a little more oversize (.01" - .02" more) than what is recomended for jacketed bullets, so I'll start with that and see if I'm in the ballpark. To slug the barrel, do you think I could "squish" a cast bullet in a vise to make it a little wider and use that?

 

[hatman1793]

Try a different powder

I am currently using Alliant's bulk powder, PROMO, along with their newer powder, ClayDot.
Both are excellent and value priced. PROMO is C95.00 for 8 pounds and is just like RedDot.
ClayDot is just like Hodgson's Clays and is a little more for the same 8 pounds.
Both work very well. PM me if you want my exact 40 receipe.....

 

[TPK]

After some more digging it has become quite apparent that the polygonal rifling of the factory Glock barrels simply isn't lead friendly. So I have ordered a "Storm Lake Barrel" from Questar and will try load variations with it once it arrives.