40 S&W, COAL and seating depth with various projectiles

[RandallOfLegend]

I just bought some bullets from Bayou Bullets, 180gr flat nose, 175gr semi-wadcutter, and 140gr truncated cone. I will eventually upload an image.

My standard bullet has been xtreme plated or speer gold dot 180 grs (Nearly identical physical dimensions). But my issue is the following. If you stack the bullets nose down there is a 0.04" difference in projectile length between my standard and the 180 gr BB FN, and a 0.094" difference with the 175 gr BB SWC.

How would you handle adjusting your loads? If I use my standard 1.125-1.130" COAL range for reloading that is some serious case capacity loss. Charging the cases will require care and consideration.

Left to Right:
Speer Gold Dot 180 gr GDHP (0.564" Long)
X-Treme Bullets 180 gr FN (0.571" Long)
Bayou Bullets 180 gr FN (0.605" Long)
Bayou Bullets 175 gr SWC (0.658" Long)
Bayou Bullets 140 gr TC (0.523" Long)

[RandallOfLegend]

http://imgur.com/2m9Zumg

Bump for Photo!

[RandallOfLegend]

A quickload simulation of Hodgdon HS6 tells me that I should go an pull the 20 SWC loads I made. I should have gotten the program before to see how seating depth affected it. At my manufacturing tolerances (shortest seating depth, highest charge) I get a max pressure load. Might be safe, but I don't make bets with firearms.

[dsdmmat]

I load to maximum oal that will reliably feed. I typically only charge target loads with the minimum needed to operate the pistol. When I go for power factor I load to meet it (as safely as possible).

[RandallOfLegend]

I load to maximum oal that will reliably feed. I typically only charge target loads with the minimum needed to operate the pistol. When I go for power factor I load to meet it (as safely as possible).

I try to load my 40 ammunition to near IPSC "Major" So 950 fps 180 grain, or 1000+ fps 165 grain. From all of my research the xtreme bullets 180 grain is a flatter/shorter profile than other plated bullets. The Bayou Bullets 180 grain is within 0.005" of the Berry's Plated 180, and the load data I have is for the Berrys. So I feel good with the Bayou Bullets 180.

The SWC 175 grain (really 178 grain) is 0.05" longer than the 180 grain flat points. So the charge I use with HS6 is 0.4 grains (5.5%) below maximum published, but I don't think I should use the same charge if the bullet is set back 0.05". Quickload predicts 35,500 PSI at my worst case manufacturing tolerance (-0.005" seating depth, +0.2 grains). If the load is to spec I get 33,000 PSI. The SAMMI max is 35k.

When I run Hogdons numbers for HS6 in quick load, I get nearly identical pressures and velocities. So I have some trust in the software for that powder. I have had a lot of load discrepancy with Accurate Arms #5, and I can't get Quickload to match the published AA data. Which is probably a topic for another discussion.