11mm Gras Bullet Diameter?

[Dhall_37]

Hey folks, I have some 348 cases ready to form up to 11mm for my gras rifle. once they are formed I'd like to get this thing shooting some lead, the only problem is I don't know what size bullet to use!

The rifling appears to be in good shape, just rusty because this came out of that RTI Ethiopia cash, Id wager that the bore isn't much off from original spec.

Unfortunately I am unable to slug the bore, I don't have any way to drive a slug in. I can run by Walmart if need be and try to find the proper size fishing weight and maybe drive it in the muzzle a tad and back out with an old cleaning rod? I did something similar with a Carcano and got a good measurement.

If any of yall gras loaders could chime in that would be great. I'm currently seeing bullets from .439 to .446 and am at quite the loss.

[GregLaROCHE]

You should really make an effort to slug the barrel. That’s the way to know for sure what diameter you should be aiming for. You’re on the right track thinking of buying the appropriate size lead sinkers. Maybe pick up a piece of brass round stock too. I’ve slugged a barrel with steel round stock wrapped in duct tape to protect the bore.

[JonB_in_Glencoe]

SNIP...

If any of yall gras loaders could chime in that would be great. I'm currently seeing bullets from .439 to .446 and am at quite the loss.

Surprisingly mine was .454 to .455

Here is the story...
https://castboolits.gunloads.com/sho...ch-appreciated

[Dhall_37]

Geeze that’s 45 cal not 11mm!

[Dhall_37]

You should really make an effort to slug the barrel. That’s the way to know for sure what diameter you should be aiming for. You’re on the right track thinking of buying the appropriate size lead sinkers. Maybe pick up a piece of brass round stock too. I’ve slugged a barrel with steel round stock wrapped in duct tape to protect the bore.

Just got some sinkers today! They are slightly too big so I may need to tap them a tad with a mallet to deduce diameter. I’m thinking when I drive them in I’ll only go I few inches from the chamber. I’m not sure if my beater cleaning rod is long enough for the whole bore.

[BP Dave]

That might work, but I don't think any of my cleaning rods is stout enough to slug a bore.

You might look at the local scrapyard to see if they have brass rods that might work. I've had pretty good luck finding various diameters and lengths. I use a short section of brass rod as a starter. And I've found that some oil in the bore makes the slug slide a little easier.

Also, my experience with a Gras (from many years ago) was that the chamber neck was not big enough to take a bullet that was full groove size. I believe I used .446 bullets with decent accuracy, except they all shot about 11 inches to the left at 100 yards.

[Dhall_37]

That might work, but I don't think any of my cleaning rods is stout enough to slug a bore.

You might look at the local scrapyard to see if they have brass rods that might work. I've had pretty good luck finding various diameters and lengths. I use a short section of brass rod as a starter. And I've found that some oil in the bore makes the slug slide a little easier.

Also, my experience with a Gras (from many years ago) was that the chamber neck was not big enough to take a bullet that was full groove size. I believe I used .446 bullets with decent accuracy, except they all shot about 11 inches to the left at 100 yards.

I just barley tapped the slug down the muzzle, it measured .446. Do you think a really fat wooden dowel would work? I might have to run by Lowes and see what they got.

I’m not sure of any local scrap yards, but I’ll go a google search and see what I can find online.

[Maven]

Try R Rice barrels: Go to this location https://www.ricebarrels.com/other%20products.html, scroll down to stainless steel range rods, which are very high quality and not expensive. They'll do the job!

[GregLaROCHE]

Just got some sinkers today! They are slightly too big so I may need to tap them a tad with a mallet to deduce diameter. I’m thinking when I drive them in I’ll only go I few inches from the chamber. I’m not sure if my beater cleaning rod is long enough for the whole bore.

You will need something as long the bore or you risk not being able to get the slug out. I’ve head of people using wooden dowels before. Before starting, run a heavy oiled patch though the bore.

[Mr. Kiss Kiss Bang Bang]

I grease the lead ball before driving it in so it takes less force to tap it through the bore. It’s fine that the lead is larger, center it on the muzzle and using a lead or brass hammer start tapping it into the bore, the excess will mushroom and shear off. Just don’t use any kind of hammer that could damage the muzzle.

[ascast]

Well, I always do a chamber cast with an inch or two of rifling with Cerosafe. You would have had it done 30 times over by now and could move on. Read the instructions. That said, my Grass shoots the RCBS 43-370 bullet just fine. It drops at .448". It really is about how big a bullet you can chamber, not the groove size. The grooves were all oversized on all of these old military guns. They shot a pure lead bullet, paper patched maybe, and relied on upset to fill the grooves. Over sized grooves just made space for more fouling to build up before cleaning was required. I bet you wont chamber a bullet large enough to fill that groove. Almost all of these old military guns have the same issue. They look like they want a bullet in the 450-452 range. Seat a 45ACP pill and see if it will chamber. If it does, try a 45 Colt pill. If not, your done with all the pounding lead in and out stuff. If yes,...well.... good luck find a 350-400 grain bullet in that diameter. Shoot soft lead with black or Unique. I liked 4759. Others will have powders, loads, etc. At 600 yds, mine shot about 6 feet left, but grouped well enough. I never refined the loading. Hang a bayonet on it, might help. Looks cool anyway. They are a left hand twist so recoil feels odd in your hand. have fun, let us know how it goes

[Dhall_37]

Will definitely let y’all know how it goes, I’ve reloaded for my Berdan 2 and even have a post on making cases for it out of 43 Spanish, so I have dipped my feet in BP loading.

I don’t cast my own unfortunately, it’s a work in progress, but a guy on gun broker has some lead pills .446 from an older Lyman Mould or accurate mould.

Once I drive a slug through I’ll report back in, also cerrosafe is on the want list!

[Dhall_37]

Alrighty, just drove a slug from muzzle to chamber. Diameter in the lands was .452!

Getting the slug started was the hardest part, then taking a beat up hoppes 3 piece cleaning rod with a 223 case on the end drove the slug down just fine. I’d attach another length of the cleaning rod as needed to keep from bending the whole thing.

I also just made up the 223 case on the end on the fly, I didn’t want the steel to accidentally drive through the slug. Just make sure if y’all put a 223 case on the end of your cleaning rod, make sure the rod stays in the case when dropping down the bore. Mine kinda missed and tore up the mouth of the case, which on a tighter bore say 338 may scratch the rifling due to the rod not being covered. I took a peek down the bore holding it up to a light and didn’t see any scratches.

This was my first time slugging a bore and I gotta say I learned a lot about what to do and not to do!

[Dhall_37]

Here are some photos of the equipment I used and the 223 case that the rod didn't quite go all the way in.

[ascast]

Alrighty, just drove a slug from muzzle to chamber. Diameter in the lands was .452!

Is that in the rifle or on the "slug" ?

[ascast]

the old Idea/Lyman molds are, IIRC, 446110 for 11mm Mauser and 446187, a 500 grner for 44-77 or 90.

[Dhall_37]

Alrighty, just drove a slug from muzzle to chamber. Diameter in the lands was .452!

Is that in the rifle or on the "slug" ?

That was the measurement on the slug. I should have said measured .452 in the grooves of the barrel on the slug.

Apologies if I misspoke.

[ascast]

I was just checking,....so your bore is 0.452", and groove is something bigger. How big a bullet can you chamber ? You might want to look into sizing down a 457".

[Dhall_37]

I was just checking,....so your bore is 0.452", and groove is something bigger. How big a bullet can you chamber ? You might want to look into sizing down a 457".

I didn’t measure the bore yet in between the lands on the slug. The widest measurement at the tips of the lands on the slug was .452. Once I fireform I’ll see what I can get to chamber.

Sorry if I’m mixing up terminology, I’m still new to this kind of reloading.

[JonB_in_Glencoe]

.452 Groove Diameter, is how most of us would say it.
While that is much larger than the norm (like mine is), it sure makes it easy to find a boolit for it.

Most would say generically, to use a boolit .001 to .002 larger than groove Dia.
BUT, I have found that a boolit that is same size as Groove Dia is perfectly fine for a single shot rifle or really any bolt action rifle ...but there remains to be, the "what fits in the chamber" thingy.