Need some help if you don't mind ... gas check questions

[flashhole]

I'd like to pick up a bullet mold for my 45-70 Guide Gun. It slugs out at .4590 and I am getting down to the last of 1500 Hornady 350 grain jacketed bullets I bought a few years back. I want to switch to cast bullets.

I cast bullets for my 40 S&W that work really well using the Lee microgroove truncated cone 6-cavity mold so I am familiar with the casting process. I have a sizer I run the cast bullets through for consistency and accuracy is good. These bullets do not have a gas check.

Following recommendations from some other threads on Cast Bullets I have my eye on a specific Ideal 457483 mold that is 378 grains but is described as a GC (Gas Check I assume) mold.

How does one apply a gas check to a cast bullet?

When in the process is the gas check applied and are there any special tools required?

My casting lead is from wheel weights.

What should I expect with this bullet if I did not use a gas check? My current jacketed bullet load pushes the Hornady 350 grain bullet at just over 1900 feet per second. I doubt I will get that velocity out of a lead bullet without severe leading.

Should I be looking at a different mold?

Any pointers or comments? Thanks in advance.

[41 mag fan]

Gc's are easy...you got a sizer, you put it in the hole of the sizer, set bullet on top and pull handle to size. The sizer will slightly crimp it on.
Basically it's just like sizing a reg boolit, except you place a gc on first set boolit on top and size.
If not wanting to put on that way, NOE sells a gc seater. I like it for using aluminum gc's.

[mdi]

I've been using a Lee push through sizer to install gaschecks on all my checked bullets (He-he, 2). On my bullets, I just put/start the check on the base of the bullet, set the bullet on the sizer "ram" and push 'em through.I've gone through at least one thousand, cause I used up one box of gas checks...

[338RemUltraMag]

Here is how I seat checks square, works like a charm!

http://castboolits.gunloads.com/showthread.php?201576-Super-simple-way-to-seat-gas-checks-perfect-every-time

[grouch]

Some mold makers(Cast Bullet Engineering) will sell you a double cavity mold with one plain base cavity for no extra charge. These are cherry cut molds, and he simply backs out the cherry to the first driving band leaving a flat base, lighter than the gas check cavity. Mine works well.
Grouch

[Boerrancher]

First off I can assure you that at 1900 fps on a plain base boolit with a 100% COWW alloy if you use the proper lube you will not get leading. If you do you have leading your lube is not right. My Father's pet load for his custom built 45-70 was a case full of 2400 on a hollow base 405 grain cast boolit made of WW. I don't know what the velocity was but I promise you it was well over 1900 fps. Most likely around 2400+ fps. I would find out if I had the guts to pull the trigger on that load.

Best wishes

Joe

[Larry Gibson]

If you want top end performance from your guide gun then a GC'd cast bullet is an excellent choice. The 457483 is an excellent choice but not for a Marlin lever action, the nose is too long. RCBS and Lee make excellent FP moulds that are excellent in the Marlin. One of those would be a better choice.

Larry Gibson

[flashhole]

Good inputs guys, this is exactly the kind of information I was hoping for.

[alfloyd]

I use the RCBS 405 grain gas checked slugs in my Marlin Cowboy 45/70.
I load them up to 1350 fps, using a gas check, and have very good results with them.
This is a fun load, not too much kick, and very good accuracy.

Lafaun

[flashhole]

I just bought this one and the corresponding bullet sizer kit from Factory Sales.

Lee Precision MOLD DC 457-340-F

[MT Chambers]

I was going to say that if you use a lube/sizer, you lube, size, and install GC with one pull of the handle, I use the Star or Lyman, Rcbs sizers.....bullets driven to higher vel.and/or pressure levels, do best with the GC.

[gwpercle]

Some of the best money I ever spent was for Lyman Cast Bullet Handbook, 3rd Edition back when I started and got the latest 4 th Edition when it came out.
Lots of realy good info in there, answers questions and has photo's and drawings to help explain things...it's my casting and reloading Bible and first go to book when questions arise.

Gary

Gary

[lylejb]

Flash,

I just went to the factory sales site, and the largest Lee sizer kit I saw was .457 . You said your barrel slugs at .459, This can be a problem, an undersize boolit is not your friend.

You can, however, enlarge the lee sizer dies by sanding to whatever size you need. You'll need at least .459, and possibly as much as .460- .461

[FishingFool]

slug a few more times and measure with a micrometer. something ain't right with that bore slugging at .459"

[geargnasher]

I have two Lee 457-340-RF moulds and they both drop right at .4575" with wheel weight alloy plus a pinch of tin, I hope yours isn't too small for your gun. Mine are also both plain-based, which limits your accurate velocity quite a bit (14-1500 fps or so in my experience with .45 caliber rifles). It should work fine to get you started, and you can even tumble-lube them as you were for your .40 with good results at slower speeds.

For higher velocity with accuracy, consider a gas-checked design, I would recommend an Accurate Molds 46-350B and a base-first sizer. I've always had trouble applying gas checks with a push-through sizer even if seating them firmly before sizing; It seems that in the process of crimping as they go into the sizer, they get pushed partway back off. Pushing them through base-first sometimes helps, sometimes not. YMMV.

Gear