Maximumbob54 wrote:I would still be curious what a 158gr SWC Or RFN would do. Bit more energy or velocity to hit them with and I bet it would still go clean through them. I'm just wondering if the use of the heavy for caliber while it may have the punch may not have the energy. You are the expert (RD) so I don't want to say I doubt you, your logic, or your ability.
Max, sorry about the delay and here is my take based on my experienced concerning the use of a 158-grain SWC or RFN.
Before I do, I must have a disclaimer; the only thing that I'm interested in is a hog & whitetail killer. I'm not interested in plinking (don't really know what that is) or punching paper. I need jacketed bullet velocity for a like weight bullet, or better, because I need killing authority downrange. I want the best possible killing authority out at 100 to 200 yards (in the case of the 357 Mag, the max I consider is 125-yards). Of course it must be accurate, I won't hunt with the bullet or load if it is not capable of producing 2.25 MOA, 2.5 if I can't get anything else to work but then I shorten the max shot I will take. The velocity I'm looking for dictates that pressure be applied to the bullet so that dictates a gas check be used (alloy treatment also becomes rather specific). Concerning the gas check, I have tried various bullets of exact design except for one being gas checked and the other being plain base and even when respecting the pressure considerations of the plain base, I have never had the plain base outperform the accuracy of the gas checked bullet. So honestly, based on my experience, I don't even consider the plain base bullet. Okay, back to the weight and nose profile.
The SWC is a cylinder shaped projectile with a bore riding nose and good meplat. The bullet body and bore rider is designed to get from the cylinder, across the gap, and into the forcing cone of a revolver with minimal upset. The meplat has great terminal ballistics (a politically correct term instead of "killing authority") but the design suffers from low BC which dissipates that authority rather quickly down range. My main issue with the nose profile is that it was designed for the needs of a revolver and does not address the chamber fit of a rifle. That has been the proven accuracy killer for me based on my shooting. The bullet starts out without any support in the throat. The bore rider is suspended in the space of the throat and you get what you get when the noses smacks the bore. If the nose were extended to meet the lead, It would greatly help the accuracy of the SWC in a rifle but we also are dealing with overall lengths controlled by limitations of the leveraction.
C358-158-SWC_90327.jpg
There is a good example of a 158-grain SWC for my use with the R92 in Lee's C358-158-SWC, but back to the revolver thing, this SWC is woefully short at a cartridge OAL 1.525". As far as shooting it, accuracy was marginal but I only intend to shoot my R92 357 Mag at game out to 125-yards. The deal breaker is down range velocity performance. The 17-grain lighter bullet does leave the 20" barrel 75 FPS faster (1865 FPS with 16.2-grains of H110, slightly faster than my favorite of Lil'Gun) but because of the low BC, at 75 yards it is already 95 FPS slower than the heavier bullet. By 100 yards, it is a 130 FPS slower which is significant in that the 357 Mag is a marginal big game rifle to begin with. Poor bullet nose to throat fit and the low BC of a SWC is a deal killer for my needs.
On to the 158-grain RN. It does have potential merit and was part of my evaluation. In that the nose length, diameter, and profile is a given for chamber fit, there is less lead after behind the front band so the bullets balance is further forward (this is in reference to my balance considerations in my previous post). So the light bullet is front heavy and less stable in flight (even before any twist considerations). This is drawing board stuff.
There are no cheap (Lee) examples to test without going through a custom design. The best I could do is put my calculations carefully to the numbers and this is from my design notebook. I believed a 158-grain bullet with the same nose profile would 90 FPS faster at the muzzle, 80 FPS faster at 75 yards, and 75 FPS faster at 100 yards. When just weight and FPS is considered, this might be the punch needed to push through the hide of a feral hog at 75 to 100 yards but the terminal effects really don't support the gain.
R92_357M_158-vs-175_termninal.jpg
When looking at a chart like the above, from bullet energy to the right I really don't see the numbers as absolutes but rather each category as an index to be compared to a similar set. In that light, the added velocity alone of the 158-grain bullet does not win out and I still have to gamble with the mismatch between center of lift and gravity which is greater than 3% (a real red flag based on my design wins and losses). In addition, the lighter weight bullet would lose a lube band. So, it sat on the design board and my trial cut money (approximately $300) went with the 175-grain bullet.
The closest cheap (Lee) example would be the Lee 358-158-RF but it is not a "C" bullet (gas checked) so it would have limited value to me. Nose length is different than what I proposed and I'm pretty sure that the Lee design did not consider fitting the ogive to a chamber throat so I'm not sure what OAL it produces and how the crimp groove and case mouth fit with the R92.
Well, that's what rolls around between my ears and is what are the details of me killing a hog out at 75-yards or better (with any cartridge or bullet). Given the complexities of night time shooting, I think the 357 Mag is better left to daytime duties where visual cues are available before and after the shot.
You do not have the required permissions to view the files attached to this post.
