[Tibor]

I recently "inherited" my father's Security Six in .357 magnum with 6 inch barrel (ported by a local gunsmith). It's mostly had .38 specials fired through it. I was loading up some of Speer's 155 grain lead SWC bullets (.358 diameter) for it the other day and decided to try the Elmer Keith push through test for the cylinder throats. There was no way the bullets could pass through those tight throats. This got me thinking about my experience at the range the other day. I had loaded the 155 grain LSWC behind 4.7 grains of Unique for a low end +P 38 Special load. I was a little surprised by the amount of recoil inspite of the ported six inch barrel. I've fired a .45 Colt Vaquero as well as an M&P .45 ACP and the recoil of the .38 seemed to be quite a bit sharper than either of these. I began to wonder if the tight throats are generating higher than normal pressures. Does anyone have any knowledge of excessively tight cylinder throats in the Security Six?

 

[ribbonstone2]

Could raise pressure enough to be noticable. Have always felt that there their is no good reason to use anything other than bullets that match the chamber throats. IF too large, using the throats to resize a too large bullet on the way to the barrel seems to increase pressure a bit and promote leading. If too small, they either lead like crazy or you have to find that fine balance of pressure that just manages to kick them up to sealing diameter.


Clean the devil out of the chamber mouths...clean them again. Slug the chamber mouths and find out what they really want. If it matches bore size reasonably well, just feed it that diameter.

 

[flintlock62]

First of all, the Security Six is one fine pistol! You definately do not want to use a larger diameter bullet than inrended for any weapon. I am nor familiar with what you used, but +p load is almost like firing a .357 magnum. Mine is a 4" barrel and ported, along with the action being tuned. What is the FPS of your load? That, in itself will tell everything with the given bullet weight. It all equates to pound feet of energy, and of course if the bullet is larger than intended for that barrel. For less chamber pressure, use .357 cases with the load backed off from full throttle. The best accuracy is most of the time obtaind from loads that are not full charges. Accuracy is more important than a fast bullet.

 

[Tibor]

According to the Speer manual the 155 grain LSWC I used is .358 in diameter. The Speer slugs are extruded and not cast, so I believe they should be on the soft side. I don't have a chronograph but according to the manual velocity should be about 815 fps. My load of 4.7 grains of Unique is the top end of "regular" 38 special loads which is also the beginning of the +P loads according to the manual. I'll try your idea of slugging the chamber throats and will slug the bore as well.