One for Muir ..... cast bullets and diameter required?

Brithunter

Well-Known Member
OK when cleaning this new 303 barrel after the function testing a few slivers of lead came out of the bore so obviously some leading was occuring(10 rnds). You did say that they were likely to be too small for the bore and you were right. This morning I oiled the bore and squished a 0.358" soft lead bullet down in diameter some then hammered it into the muzzle and got a nice formed plug of the first 0.320" of the bore. We know that the land diameter is a smidging under 0.302" as it leaves trace marks on the 0.302" front portion of the cast bullet so it's about 0.301" and it appears that the groove diameter is 0.315". This was measured by roling the bullet round on the anvil of the micrometer and the reading taken that just allowed the bullet to rotate (Five lands and grooves).

This means the groove depth is 0.007" and my commercial cast Gas Checked bullets are 0.004" undersize which is never going to work without leading :cry:.

Now do I save up and get a custom mould or would using 0.308" cast bullet and paper patching be an idea? .......... Or get a mould for the 32-20/32-40 (0.321") and size it down the required 0.005". I tried looking for an early 8mm mauser mould as they would be 0.318" but failed to find one :(.

Following this I guess I will have to get either the Saeco or the Lyman 450 lubesizer working and the proper dies for it/them.
 
Kev, how do you find the time to plant those trees!:D

A= I don't. Was going to cut the grass around the bungalow this afternoon then start on the field (that takes a day at least) but Mother wants to go see a garden in the National garden scheme and I got nominated as driver :rolleyes:. Oh despite the rain yesterday it only dampened the top of the soil and we have huge cracks in the ground which is killing my trees by exposing the roots :banghead: one moment it's too wet and flooded then it's like a darned desert or dried up lake bed.

BTW the next project is already in hand :p re-building that tatty ole BSA 1st Pat Monarch .270. The stock will get slimmed down in the forestock and wrist and a new finer chequering pattern executed. The barrel which is fairly worn will be replaced with a new CF2 7x64 one then it will be re-chambered for the .280 Ack Imp cartridge. We are waiting to hear about the reamer at the moment and I have my eye on some dies already ;) the cases well Midway UK stocks them marked .280 AI but to start I'll probably fire form some .270 cases as I have a few spare around :lol:. Saves the ole Monarch from the scrap and stops the Plod moaning about yet another .270 Winchester chambered rifle :D.

Keeps me out of mischief ............................... most of the time :D.
 
Sounds good to me, although I don't agree with plod,(as usual), never have enough .270's around!.......... me , up to my knees in dirty patches & wipeout splodges!:D
 
Well Finnbear I have Four rifles currently chambered for the .270 Winchester cartridge and should be picking up another Majestic Featherweight so that would be Five and they is moaning at the four :rolleyes: .

The plan is to have this one threaded for a mod assuming it's shoots nicely. It already has a splice to the schnable tip due to someone pulling the sling loop out which is why I passed on buying it before. Then I got the one I used with John for the Buck which apart for the recoil pad being replaced is original. This new one will be a light stalking rifle to take a Sound mod ;) the P-H 1200C in 25-06 is darned heavy :( weighing about 11lbs with the mod and Bi-Pod fitted.
 
Well Finnbear I have Four rifles currently chambered for the .270 Winchester cartridge and should be picking up another Majestic Featherweight so that would be Five and they is moaning at the four :rolleyes: .

The plan is to have this one threaded for a mod assuming it's shoots nicely. It already has a splice to the schnable tip due to someone pulling the sling loop out which is why I passed on buying it before. Then I got the one I used with John for the Buck which apart for the recoil pad being replaced is original. This new one will be a light stalking rifle to take a Sound mod ;)
the P-H 1200C in 25-06 is darned heavy :( weighing about 11lbs with the mod and Bi-Pod fitted.
Sounds like a candidate for a bi athlon type sling!
 
Yeah I was going to go that way but things didn't work out with unexpected things cropping up. The 25-06 will get used on short walks and high seats for now until I can get the thing sorted out.
 
Ahhh for when Muir pops in ................. I have been in touch with Veral of LBT and have enquired about the cost of the lead throat and bore slugs to see what size throat and to check for any inconsistances in the bore. At the moment am considering all options as to cast bullets.
 
Howdy Gents.
Sorry for the delay, I was down in Texas for a few-four days watching my daughter graduate from Highschool and doing some ammunition testing/QC work. Sticky hot in Texas....

Brit: The .315" groove diameter is about right. I routinely find this dimension in my .303 rifles. You can bet that the .315" is a good starting point for a bullet. I know/knew Veral Smith. Before he went to prison on a tax hiccup (and the man is not a criminal, by the way) he built me a copy of the Lyman #314-299 bullet. (Or the "Ideal #311-299" as it was known then) It it an excellent mold and he is a fine craftsman. Do not get that .321 bullet and size it down. Excessive sizing is worth paying money to avoid. As to measuring the throat, you can just take one of those .375" lead balls and drive it into the leade if you wish, then tap it out. An easier way is to look at your fired case. If you can get an accurate measurement on the inside diameter of the case mouth then deduct .0015" from that and you'll have the maximum allowable diameter for a hard cast bullet. You didn't mention the load. What was it?? Got your PM about the barrel. Sounds good.~Muir
 
Ahhh the load tried was loaded several years ago for playing with the ME AC11 in 303 I had and it seems I didn't write it down :oops: so I "think it was Reloader 7" if it was Rel 7 then the charge was 27.0 grains.

Now measuring the inside neck of the fired cases with a digital caliper I get 0.316" so it would appear that a cast bullet of 0.315" is going to be the maximum size and of course that is groove size and not 0.001" over groove size as it normally accepted as the required size ............................. Hmmmmm I thought this was going to easy :rolleyes:. Oh well back to the drawing board :banghead:.

How did the graduation go?
 
I would not worry about the relative diameters until you shoot a full power load and check the throat via that casing. Usually they run .317" and I suspect that the casing you loaded with RL-7 didn't give optimum obturation. (Boy! Spell Check doesn't like that word!)

Graduation was nice, thanks. I hadn't seen my daughter in two years. I flew to San Antonio Texas and drove 400 miles to the graduation, arriving 35 minutes before it started at 8:30PM. Twenty minutes after it was over I was driving back to San Antonio so that I could be at the test facility at 8am. It was a hectic trip but I'd do it again to see the little one.~Muir
 
Hmmm you might be right on the reloader charge so looking back over the PM's I saw you used a heft does of 4350 in the 8x57 so having some on hand I looked at the Lee powder scoop chart and used a 3.4cc scoop which threw a charge of 46.0 grains dumped it into a sized primer case after expanding the neck with the Lyman (M) die and plonked a cast bullet on top. This is a compressed load, I didn't squash the powder just seated the bullet until resistance got stiff, and checked the cartridge would fit into the magazine then muffs on walked out back and fired it. As it's an unknown load and even bearing in mind the P-14's strength I held it away from my face and squeezed the trigger. One sharp report and I have a formed case.

The digital calipers tell me the case neck insdie diameter is 0.3165".

Comparing cases fired in thsi rifle it's not possible to visually see from looking at the primers which load was the Reloader 7 (?) or the IMR 4350 the only visual difference is the noticably more apparant expansion ring at the web but that could be down to this being it's third firing and second reload in this case? On cleaning the barrel there was tiny bit of lead on the patch, not surprising with an unsize bullet and the added velocity, didn't use a target and only aimed at the backstop so we don't know if it shot anywhere near to the sights. Interesting little experiment.
 
It looks like .315" is your baby. Don't worry: there are no hard and fast rules to cast bullet shooting and .315" may be THE load for your rifle. I like heat treating bullets I shoot with those kind of charges but when you get a mold we can talk about that. The Lyman #314-299 might be your best and most available bet. It uses .30 caliber gas checks and should cast .315" and a little. Get that mold and a .315" sizer die and you should be set. If you were here we could have this all sorted out in a few minutes!

An alternative would be that Lee made design of mine. I could contact Lee and see how much that would cost.~Muir
 
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