45-70 Mold: Gas Check or Not?

[RG1911]

I've been dealing with Accurate Molds for a mold for my Marlin 1895 45-70 that has the oversized bore. I'll need a mold that can cast a bullet that can be sized/lubed to .462" using an approximation of Lyman #2. (Also have wheel weight lead, pure lead, and linotype.) Looking at the molds for 350-360-gr bullets, I'm caught between one that takes a gas check and one that doesn't.

Is there a definitive answer to the question or is the decision left to chance?

Thank you,
Richard

[sukivel]

Both of my 45-70 molds are plain based and I load the 457125 at almost Ruger #1 levels with no problems.


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[Bird]

I have cast more than a few gas checked bullets for the 45-70, and use them for the higher velocity loads. They are quite a workout for the shoulder.
I will be moving to the plain based bullets loaded to the 1300 fps range as they are less punishing, and accuracy is the same as with the higher loads. More enjoyable to shoot, and one less step involved than with the gas checks.

[robg]

how fast do you want to go? over 1400fps you might need a gas check .personally i went plain base as i dont need to beat myself up and i wanted to keep costs down .

[oger]

You don't need a gas check for any 45-70 unless you are using an awfully soft bullet. I make an old 530 gr Hoch out of WW + tin for a friend that he pushes over 1700 FPS in a 45-120 with no leading.

[USSR]

Richard,

Forget about gas checks, just one more thing to search for and hope you can buy. Here is what I ordered in that weight range: https://www.accuratemolds.com/bullet_detail.php?bullet=46-345B. Whenever ordering from Tom at Accurate Molds, your mold will cast 0.002" over the size you specified for the alloy you specified. So, if you want to end up with lubed and sized .462" bullets, specify a .461" mold and you will get .463" bullets that you can lube and size down to .462".

Don

[JonB_in_Glencoe]

The definitive answer to the question is... you don't need a GC, until you do.

I don't mean to be flippant, my first 45-70 mold was a NOE two cavity 405gr mold, with one cav GC and the other a plain base.
I found I didn't need a GC for my loads, with my rifle.

[longbow]

In my experience if bullet fit is good a gas check is not required except possibly at Ruger #1/Siamese Mauser top end loads.

I had a Siamese Mauser converted to .45-70 in the 1970's. I had three moulds for that gun: Lyman 457125 (500 gr.), Lyman 457124 (385 gr.) and Lee 405 gr. FP. I loaded all to top end Ruger #1 data because I was young and foolish! All were PB boolits and the only leading I got was with the Lyman 457124 at max. loads and that was just in the last inch of the barrel. My solution was to add a .410 fiber wad which solved the leading. Accuracy was good.

I later bought a Marlin 1895 so had to load a bit lighter for it, though those are plenty stout for most applications and can be quite punishing. I had no issues with leading using top end Marlin 1895 load data. Of course after being pounded silly by excessive recoil using the Ruger #1 data I found the top end Marlin loads much nicer to shoot and still plenty for anything I needed. These days if I still had my .45-70's I suspect I'd be using low to mid range Marlin data and be quite happy. I have 12 ga. slug loads to beat me senseless now! Thinking I should download those a bit too!

I really had no issues with PB boolits in the Marlin or Siamese Mauser at any reasonable load level.

I am lazy and cheap so if I can get away without a gas check I do. Nothing wrong with gas checks except cost and extra handling. I don't think you'll need them for most load levels in .45-70 though unless you want or need top end loads for Marlin or beyond then a gas check wouldn't hurt and could help.

YMMV

Longbow

[RG1911]

I would like to thank everyone for the thoughtful recommendations. Since my right shoulder has been broken and more recently had major surgery, being beaten to death is way down on my list of desirable activities. So velocity shall be restrained and GC not needed.

Cheers,
Richard

[Harter66]

I recently loaded some 250 gr RNFP to 2000 fps in WW in an 1895G . I won't be shooting any more of those , not because of lube or leading but because of the recoil concussion .

WW-pure 50/50 shoots fine into strong lever action loads though would probably close things up a little if it were closer to 75/25 in the Lyman 458193 .

Dead soft with the 458132 Postell , 460-543 @ 535 gr NOE , would probably be fine in pure for subs .

[GregLaROCHE]

If you are going to powder coat, I would definitely go with a plain base. I have a 500 grain GC mold I plan to modify to plain base.

[USSR]

I would like to thank everyone for the thoughtful recommendations. Since my right shoulder has been broken and more recently had major surgery, being beaten to death is way down on my list of desirable activities. So velocity shall be restrained and GC not needed.

Cheers,
Richard

Richard,

If that's the case, you should consider a lighter bullet. I designed this one and Tom made it for me: https://www.accuratemolds.com/bullet_detail.php?bullet=45-290K. It's my favorite bullet for my .45-70, as it shoots well and doesn't punish you.

Don

[Targa]

Richard,

Forget about gas checks, just one more thing to search for and hope you can buy.

Agreed 100%

[Chill Wills]

Richard,
If that's the case, you should consider a lighter bullet. I designed this one and Tom made it for me: https://www.accuratemolds.com/bullet_detail.php?bullet=45-290K. It's my favorite bullet for my .45-70, as it shoots well and doesn't punish you.
Don

I wanted to check out your bullet but the link took me to a revolver bullet 0.454" diameter. ?

[USSR]

I wanted to check out your bullet but the link took me to a revolver bullet 0.454" diameter. ?

Oops, listed the wrong link. Actually, the mold I had Tom make was a variation of this mold: https://www.accuratemolds.com/bullet_detail.php?bullet=45-290H. Don't let the listed diameter fool you, you tell Tom what diameter you want (in my case .460") and he cuts them to whatever diameter you specify.

Don

[Roger Kehr]

I'm glad I ran across this post. I am currently building a 45-70 on an '86 Winny. I will go with a plain base bullet and W/W. I'm thinking 350 -375 grain bullet. Right track?

[Char-Gar]

I've been dealing with Accurate Molds for a mold for my Marlin 1895 45-70 that has the oversized bore. I'll need a mold that can cast a bullet that can be sized/lubed to .462" using an approximation of Lyman #2. (Also have wheel weight lead, pure lead, and linotype.) Looking at the molds for 350-360-gr bullets, I'm caught between one that takes a gas check and one that doesn't.

Is there a definitive answer to the question or is the decision left to chance?

Thank you,
Richard

The answer is not left to chance. The vast majority of the time a GC bullet will produce excellent accuracy over the entire velocity range and is far more tolerant of alloy temper than plain base bullets. The fly in the ointment is that a GC does cost money. A plain base bullet, if of the proper size and temper will do as well as needed to about 1,300 - 1,400 fps.

My 45-70 molds all wear gas checks.

[MostlyLeverGuns]

With the 45-70, an upside down gas-check loaded tight against the bullet base can also allow plain base bullets to be used at speed, gas check should be snug fit in case so bullet seats it into case. With the light Marlin 1895 recoil can get very unpleasant, even with lighter bullets when velocity gets higher. 300gr at 2200fps, does shoot flat though, works fine on elk and moose. My rifle bullets do usually wear gas checks as accuracy is easier to achieve at velocities suitable for shooting over longer ranges(over 100 yds), wind, too much drop, stuff like that, where velocity helps.