cerrosafe, check me out on this plan and give advice please

[BJK]

OK, consider me to be a total casting noob and you won't be off by much. My experience is #4 buckshot and 12ga slugs. I have NO experience with casting for rifled arms.

It was suggested to me that I slug my barrel. You have no idea how reluctant I am to pound even pure lead into the muzzle of an accurate firearm. Enter cerrosafe.

One handgun is a .300BLK AR. I should have a chamber casting, so I was told. If I get the bore measurements from ahead of the leade that will tell me all I need w/o playing near the muzzle, correct? (except for the cleaning rod at the muzzle pounding the casting out of the chamber) The muzzle on this gun is not so easy to get to but I suppose I can get to it if I must. Or would you forego the chamber casting and just take a muzzle casting?

Another rifle is a 9mm that doesn't have an easily removable barrel. But I can easily get to the muzzle. For this I'm thinking of just getting what I need from pouring into the muzzle and pounding the casting out from the chamber end.

Does this sound like a plan that will get me what I need? I'm definitely open to suggestions.

[pworley1]

If you use cerrosafe you will need to keep these properties in mind to get accurate measurements. CerroSafe® is a special alloy of Bismuth, Tin, Lead and other metals, that shrinks slightly during the first 30 minutes, to allow easy removal, then expands to exact original size in one hour. We recommend CerroSafe® for making a chamber cast.

[Burnt Fingers]

Just size to .310 for the 300 BO and .357 for the 9mm.

Chances are you'll be fine with those diameters.

[RickinTN]

Just size to .310 for the 300 BO and .357 for the 9mm.

Chances are you'll be fine with those diameters.

Yep. Forget all the other headaches and just do this. Probably work out quite well for you.
Rick

[mdi]

FWIW; Slugging is no big deal. I normally slug every new firearm that comes into my possession (I even did a 22 rimfire). Soft lead slug generously lubed, and a "non-marring" mallet, plastic works well and a brass rod of appropriate length. Mount barrel/gun solidly, start slug, and when even with the muzzle, use a brass rod to drive the slug through. Measure with micrometers. And of course, think about what you are doing and keep any steel tools away from the muzzle. Tag and save the slug for future reference. It takes longer to type this method than actually slug a rifle...

(I use a lot of "case slugs"; melt some lead and pout into a case of appropriate diameter, or one for the gun being slugged. Remove with an impact bullet puller and you have a tapered slug of correct diameter).

[Der Gebirgsjager]

I tend to always go with the more practical advice, and I think you're getting it here. Bore and chamber measurements can and do sometimes vary, but I'd go with the standard specs and cast and load accordingly until I became convinced that there was a problem--which there probably isn't.

Cerrosafe can be difficult to work with. It's great when all goes according to plan, but sometimes a rough chamber won't permit an easy release and one has to melt it out again.

I've slugged many barrels, but rarely from the muzzle, and do it from the breech end when possible. It sounds like one of your rifles is an AR-type. It's not too difficult to remove their barrels and have access to the breech.

But, as already noted, it may not be necessary at all.

DG

[Conditor22]

Even if you slug your barrels, that doesn't always tell you what that gun will like best it gives you a good place to start.

for common US firearms, you could get away with the "standard measurements"

I get excellent accuracy from my AR sizing to .309.

In 9mm's, my European guns have larger bores and need boolits sized .359-.360 where one of my Ruggers prefers .3565 and the Sig does best with .358.

If I didn't slug/or chamber cast my barrels I would start with the basics and do a little experimenting with sizes.

I eventually plan on testing my favorite loads for a couple of my 9mm's with 6 different sized boolits.

My 2¢

[Rcmaveric]

I used it once. Made a huge mess and it was a pitta. Indont like using it. Took me all day to clean the dribbles out of my chamber where bolt locks in. I won't use it again.

Pound cast and slugging a barrel won't hurt a barrel. I mean come on, you shot jacketed bullets out of it and people are shooting copper bullets. Just dont use something harder than the barrel to drive the bullet down it and you won't hurt it.

Sent from my SM-N970U using Tapatalk

[BJK]

Thanks gents! That saves me a lot of hassle. I'm glad I asked.

[gwpercle]

Slugging a bore is no big deal if you know how to do it ... Ignorance raises it ugly head and will ruin a good rifle in short order .
Lets see what Lyman Handbook has to say about their data .
300 Blackout , size cast .... .309"
9mm Luger , size cast ... .356"

So if we bump Lyman's size up a notch ...
.310" for the 300 blackout
.357" for the 9mm Luger
Should be just right and without doing a pesky slug job or risky CerroSafe pour .

I have no experience with the 300 BO but with 9mm Luger all 4 I have loaded for worked fine with .357" boolits ...
Gary

[BJK]

Thanks Gary. Yes, I'm just going to size as suggested. If I have problems I'll need to take it from there.

[Alstep]

I found that when pouring cerosafe into the chamber, punch it out as soon as it sets. Don't wait. The first time I tried it, I waited the recommended time and it set up solid. Had to use a heat gun to melt it out. Otherwise, it worked fine.

[Alstep]

I found that when pouring cerosafe into the chamber, punch it out as soon as it sets. Don't wait. The first time I tried it, I waited the recommended time and it set up solid. Had to use a heat gun to melt it out. Otherwise, it worked fine.

[cas]

I've used cerrosafe several times to check bore diameter without issues. The only problem is you really can only check the throat and the muzzle, usually the largest parts of your barrel. (obviously if you're looking for barrel choke, this is no help) But it works great for old, oddball, who knows what the heck size it may be... stuff.

That said.. I agree with all here, you're really over thinking it for those two calibers.

[greenjoytj]

BJK- I think your wasting your time slugging the bore and chamber casting for such modern firearms and cartridges.
Do you own a blade or ball end micrometer to measure the chamber cast or bore slug?
Without a measuring tool of this kind your wasting your time, a vernier calliper is not accurate enough.
Are your planing to purchase a bullet mold? Check the mold makers tolerance his machines can cut to. It’s probably + or - 0.001” or more.

[BJK]

I absolutely agree. I was overthinking it, but what I proposed was suggested to me here (slug the bore) and the chamber casting for the .300BLK was suggested over on that website. I have shelved the idea and I'm just going to size to .357 and .310 and go from there.

[Wayne Smith]

I found that when pouring cerosafe into the chamber, punch it out as soon as it sets. Don't wait. The first time I tried it, I waited the recommended time and it set up solid. Had to use a heat gun to melt it out. Otherwise, it worked fine.

Al and I have found the same thing. It's useful when you get a gun and you don't know the chamber.