Setting up a sizing die for bottlenecked cartridges

[RiverRider]

That works and is similar to how I sometimes develop a new load with a familiar rifle, but it's not a ladder test.

 

[deemus]

That works and is similar to how I sometimes develop a new load with a familiar rifle, but it's not a ladder test.

educate me.

 

[RiverRider]

A ladder test is when you load one round each of a range of charges a desired increment and fire them all at the same target, keeping track of where each one hits and then analyzing it.

IOW, I might load up one round each at 25.0, 25.2, 25.4, 25.6, 25.8, 30.0, 30.2, and 30.4 grains. I then fire them all at the same target. They tend to be scattered as expected, but I notice that 25.6, 25.8, and 30.0 grains are clustered together in an obvious way. Based on that I would do further testing at 25.8 grains because I infer that slight variations of powder weight don't affect the point of impact as much as other charge weights do. That's the theory of it, anyway. It supposedly works best at longer ranges, like 300 yards and beyond. I think the method is most popular among the long range crowd, and they tend to select rifles and bullets strictly for accuracy and it's my opinion that this is why you (they) need to shoot ladders at longer ranges. Their rifles are more forgiving.

I have employed the ladder method one time, and at only 200 yards but that was with a rifle that's just not going to shoot like a rifle built for competition. Mine was (is) a .Model Seven in 6mm Remington, the only real "custom" built rifle I have ever bought (besides a couple of econo-customs built on 98 Mauser actions). It's nothing extravagant at all. The reason I used the method was because I had bought an 8-pound jug of pulldown powder at an excellent price---the catch being that I was given only ONE suggested load with a defined velocity for it and it was not a cartridge I load. So what I had to do is try to identify the powders it was likely most similar to, which I did (I thought it was very much like the old H450, long discontinued). I still was not prepared to treat the powder as though it really WAS H450. Instead, I loaded up about 15 rounds, all with different charges, and starting at a very conservative charge weight. Increments were 0.5 grains. Here is an image of the results:

Loads 13, 14, & 15 clustered nicely and as it turned out, my charges seemed to be within the limits of safety based on velocity monitoring. Number 15 seemed to be the one to go with because it impacted right between 13 and 14. After further testing, I ended up adding another 0.2 grains to the load, and it shoots MOA with good consistency at 200 yards. One interesting thing about this load is the bullet I used, the PRVI 100-grain Soft Point. I tried it because it was very inexpensive and readily & reliably available, plus I wanted to see how well it would work on hogs (I still haven't killed anything with it, though).

One more thing about that pulldown powder...I can't be 100% certain, but it sure does load and shoot like W 780 Supreme. That may be what it is, or it may not. I dunno. It just works, so I bought 16 pounds more.

 

[RiverRider]

Another approach I have used more often seems to be pretty good when working with something brand new. Once I become familiar with a rifle and how it shoots a certain bullet I go more with my assumptions, but with new stuff I try to avoid assumptions. The consequences of bad assumptions are just too serious so I do something a little different...

I'll load up pairs at modest increments and shoot two-shot groups. I monitor velocities when I do this because that's the best way to get a ballpark estimate of pressures, which is really what this exercise is all about. I'm looking for a pressure limit. The two shot groups are just a way to detect velocity spreads at a given charge, for one thing, and to eliminate charge weights right up front...or even an entire range of charge weights. A two-shot group won't necessarily tell you what's good, but it can sure tell you what's bad.

If I could shoot in my own backyard I would do things differently, but I can't and I don't. I sometimes try to kill two birds with one stone, so to speak.

 

[benenglish]

If you're still thinking about that pistol build and you asked for my suggestion, I'd point you toward the 6mm ARC.

We're thinking the same on this subject.

For pistol silhouette, which I doubt I'll ever do again, I just need a heavy-for-caliber bullet of .224 to 6.5mm trucking along at ~2400 fps from a 14" bbl. 6mm ARC is one of at least a dozen answers to that question. (ETA - For foreign competition under IMSSU rules, .224 is prohibited so 6mm is the sweet spot.)

My next serious bench pistol will be an XP in .35 Rem so I can learn about shooting cast bullets.

 

[RiverRider]

I'm not well versed at all on the rules of the pistol games so I do not know what the restrictions are, or what's good or bad.

Personally, the only application where I would consider the 6mm ARC and/or 6mm AR would be in the AR15 platform. The 6 AR/ARC options give just about the most bang you can get out of the platform if you intend to use it at any kind of extended range (but the 6.5G is right there, too). Even so, I wouldn't restrict myself to the 2.26" cartridge length in any firearm if it wasn't necessary. Some guys like the Grendel and the ARC in compact bolt guns, though. Different strokes and all...

You just want to maybe shoot cast, or do you want to get into casting yourself? Go down that rabbithole and you may never see the light of day again.

 

[benenglish]

I'm not well versed at all on the rules of the pistol games so I do not know what the restrictions are, or what's good or bad.

In the pistol game, you just need enough momentum at the steel target to knock it down at 200 meters or 500 if you're lucky enough to be near a club that shoots the longer range games. That longest range target weighs ~55 pounds. Bigger and faster isn't better, though. No one needs to deal with excess recoil. Also, muzzle velocities over 2500 fps may damage the close targets and get you disqualified.

Bottom line is that a 6mm with a ~115 grain bullet at 2400 will do the job. If you shoot a club with poor quality target stands that absorb impact, going up to 6.5 mm and a heavier bullet works. Out of a 14" barrel, there are more ways to get those numbers than I could ever memorize.

Under European rules, they shoot half-size targets. Everybody would shoot a .223 with 75 grain match bullets if they could. To keep some connection to the concept of being a simulation of a hunt, the International rules require a larger bore size. Not that I'll ever make it over there but, man, there are a couple of matches in Europe I'd give an appendage to shoot at least once before I shuffle off this mortal coil.

You just want to maybe shoot cast, or do you want to get into casting yourself?

That's the question I'm asking myself. I've got the barreled action, the trigger, the chassis, and the bench rests. I just need to screw all that together and give it a whirl. However...

Go down that rabbithole and you may never see the light of day again.

...that's exactly what I'm afraid of. Or enticed by. I don't know which.

 

[RiverRider]

That's the question I'm asking myself. I've got the barreled action, the trigger, the chassis, and the bench rests. I just need to screw all that together and give it a whirl. However...

...that's exactly what I'm afraid of. Or enticed by. I don't know which.

You do realize some guys would advise you to take the leap just because misery loves company, I'm sure.

Just kiddin. Casting can be a relaxing hobby or it can be back-breaking work...just a matter of perspective, I suppose. There's a helluva lot more to know about it than meets the eye, though, and that makes it pretty interesting if you wanna dive deep. For my part of it I only began casting because I wanted cheap bullets at the beginning, but the truth is that I found cast bullets for handguns to be no handicap whatsoever. Rifle bullets are another story and I am not going to read that one. Nope. Just NO.