Rifle casting questions 308

[Rgmcfarland]

For your review, I look forward to your feedback. I figure this stuff out regular by doing it and use The forum as a baseline. This time I am going to ask you people to shoot holes in in my ideas In Hopes of learning faster and having a bit more fun with my trials, and maybe saving some time. Screwing up my handguns are a quick fix, leading up my rifles takes a lot more time and effort.

The mold is an unused lachmiller 311-169-pt. Recent events have put my inventory for all handguns at staggering levels, all my rifles are well stocked except my 308. So I’m bored and ready for a new challenge. I have near 30 lbs of mix checking on my hardness tester between 18-20. Who knows how much 12-14 I have.

The forums say this bullet works well to about 1600fps, so now the questions. Temper your responses with this info, I cast thousands, I lube/size in a 450, i hi tek coat, I push through size, I hand press, single stage, and run 550. I load 9 calibers. I chrono when it means something.

1. I shoot my m1 carbine lubed and checked at 2000 FPS with no concerns, I shoot my 327 fed with 12-14 hardness without checks hi tek with no concerns. So why should I check these 169’s? I think I can hi tek this gc bullet and run it up to anything under 1800 FPS while I find the castings sweet spot for me. I don’t even see why I need to run my hard lead for this, 14 hardness should be just fine 1600 and below.

2. I’ve never checked boolits in a Lee push through, even if I don’t need them I will want to try some hi tek checked once the sweet spot is found to see if anything changes. Anything unique that makes a check better on a push through I should know? I’m pretty happy with the hi tek, I can lube size if that ends up the best option but I don’t see why it would.

3. I primarily want to put together a round for my 308 long ranger for fun 200 yds and under, my normal game king bullets are getting pretty expensive. I also have two pretty neat 30-06 bolt guns. I expect that once I’ve tailored the 308 case to my goal I can the chrono the same load in the 30-06 case and increase the powder to reach the same FPS, I suspect the round would be slower as the larger case should have a lower pressure based on case volume.

4. My ballistic tables show that a guesstimate of a g1 0.276 on the cast and an advertised g1 of 0.404 on my game kings on a 100 yd zero should mean no necessary changes to my sights keeping me on 6 inch steels out to 150 and a high hold out to 200 before she drops through the sound barrier. If this sounds true enough for trials this would be a blast lever round to play with and really drop my cost per round on all these rifles. I am really wanting to make this work as I can change to my game kings and jump right back to the 4-500 yard steels with no changes.

[sutherpride59]

I haven’t played with cast boolits and long range but I can tell you that gas checks perfect an imperfect base as well as raise you max fps. I would say try some without gas checks and compare them with checked rounds but I always get an increase of accuracy with gas checks on lubed rounds. You max fps though is a combination of boolit fit, hardness, checked or not, gun powder(psi is the determining factor here along with pressure curve), seating depth, lube or coating, bullet shape, and gun. I normally find what works with everything else then push the boolit to the point of failure or high pressure signs and see what is the most accurate. I also like to cast and load two lots of different hardness to see what works better. I mostly target shoot and don’t have much opportunity for hunting so that’s the approach that has so far worked for me. The biggest piece of advice I can give though is to take a notebook with you and record all the data, post several targets and record what changes with different variables and record it because even at the age of 30 I still forget what I had for lunch yesterday much less how well my boolit combinations shot.

[Dieselhorses]

If your question is "gas checks vs no gas checks" then it depends on a few variables. If your velocity is going to exceed 1200 FPS (mainly concerning pistols) then yes use them. In rifles, referring to .308 mainly, if your mold is a gas check mold then use em. I powder coat everything I shoot and the only rifle caliber I don't bother to check is .223 despite traveling 3000 FPS, but my alloy hardness is above 20 BHN.

[waco]

Try them both ways and let us know how they shoot.

[higgins]

I use checks on all my .30 rifle bullets, which are shot at 1200-1500 fps. The bullets I use are GC design and I put GCs on them. I think that makes for better accuracy and cleaner bores with both grease and LLA lubes.

[charlie b]

To the OP:

If a bullet is designed for a GC then it is more likely to perform better with a GC than without. It is simply a matter of having the most perfect base you can get. A GC design without a GC means you have two critical edges, the last driving band and the circumference of the GC 'neck' on the bullet (and if it concentric with the bore). But, as mentioned you can try both and decide for yourself. An additional note, powder coat makes the GC not necessary to prevent leading at higher velocity, unlike conventional lubed bullets. If you have a plain base bullet design, then powder coating will let you drive it to a higher velocity.

Keep in mind when reading this that my cast bullet accuracy in my .308 is good for MOA or a little better on most days. I have several 1/2MOA groups at 200yd, but, not consistent. I am also a paper puncher so I care little about ultimate velocity, only that the bullet make a nice clean hole at the center of the target :) I normally shoot at 200 and 300yd, but, every now and then I shoot out to 600yd. Currently I am not good enough to shoot slower cast bullets at 600 to MOA with any kind of wind. It is not a function of the bullet, just the shooter :)

I install all of my GC with a Lee push through sizer. I cast the bullet, install the GC and size (yes, without lube). Then powder coat and size again. I then sort by weight down to 0.1gn.

Velocity. It is basically a function of barrel twist, velocity and lube (or powder coat). A proper lube with a medium hardness bullet is usually good for 2000fps with a 10 twist .30cal (which is what I have). Slower twist and you can probably go faster. Powder coat I have not found a limit when talking about leading, ie, there is none at any velocity I have tried. But, higher velocity will aggravate any issues with your bullets. When you spin something that fast then irregularities will make a difference. If you can cast and coat a perfect bullet it will perform as accurately as a jacketed.

I have found my best accuracy is somewhere around 1800fps but I think this depends on your barrel (length, weight, twist, etc). You may find that anything up to jacketed velocities are better for you.

The good thing about PC (IMHO) is I can change from PC to jacketed in one range session without any issues.

For really inexpensive fun load up some subsonic loads. Some of mine have been really accurate at 100yd. I have a bunch of Blue Dot that I use for this, but, many other powders will work as well.
http://www.gmdr.com/lever/lowveldata.htm

Last, bullet fit to bore. Next to a perfect bullet base, probably one of the most important factors. I use bore riding bullets so two measurements to worry about. My rifle seems to like .309 base dia and .302 nose dia. I size and seat them to be a 'jam' fit in the chamber/throat. If you are using 'normal' conical bullets then just bore dia is key. This becomes an issue in your case if you are going to load for more than one rifle in the same caliber.

[MT Gianni]

Lachmiller has been gone for 50+ years but I believe that bullet is the squib bullet designed by a Mr Squib simply by the 311 169 gr pt. It's Lyman copy is 311413 and was designed to be shot at low speeds, up to about 1500 fps. I believe spending the money for a modern design like the Saeco 315 or it's NOE copy would better fit what you want to do.

[RU shooter]

Lachmiller has been gone for 50+ years but I believe that bullet is the squib bullet designed by a Mr Squib simply by the 311 169 gr pt. It's Lyman copy is 311413 and was designed to be shot at low speeds, up to about 1500 fps. I believe spending the money for a modern design like the Saeco 315 or it's NOE copy would better fit what you want to do.
This is spot on in my experience with the squib bullet 12-1400 fps it shoots great try and push it and nothing seems to work . Long unsupported noses are hard to get to shoot well at speed , if one would have a plain base design of that bullet it would help a lot