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Is It Safe for the Same Weight?

2K views 24 replies 9 participants last post by  noylj 
#1 ·
Gotta quick question for you. I cast some .308 bullets that are weighing in at 188 grains however I'm not seeing the billet in my Lyman Third Addition. There is a 187 grain in the manual however a completely different shape. Do you think I'd be safe using the starting load? 23 grains IMR4198 at 1653fps. My hunch is yes but I'd like to avoid screwing up my '03 Springfield.

:)
 
#5 ·
So just to be clear, the shape/olive of the bullet doesn't impact things all that much?
 
#6 ·
Some. A bullet with a long pointed ogive is normally longer than one with a short round-nose.

Let's say, making up numbers, the pointed bullet is 1.225" long, while the RN is 1.100 inches.

If you were to seat both bullets to the same cartridge overall length, that would mean the pointed bullet would be sitting 0.125 (1/8") deeper into the case. Being seated 1/8" deeper means that you have that much less powder capacity. Less capacity means that, with the same charge, the pointed bullet would have much more pressure.
 
#8 ·
No, bullet shape impacts how the bullet performs after it leaves the bore, mass has more to do with how it behaves inside the bore, mass is nearly identical between the two shapes so you will be fine, just start low and work up to the sweet spot.

You might find data on the bullet shape and weight you want to use in another manual, that's why you should have more than one manual to refer to when you develop a load.
 
#9 ·
To me this question is a lead in to the question, Why do you have a bullet that you don't have load data for? I know that in these times there are limited supplies out there. I cast so I always have a bullet to reload that I have data for.
 
#10 ·
Pretty simple answer. A friend was very kind and gave me the mold as a gift. I cast 150 rounds a while back and they've been sitting there, waiting for me to empty some brass so that I could give them a go. Finally did that this week and you know the rest of the story. I will look for a book that has the information I need then I'll be good to go.
Thanks
 
#13 ·
Personally, I'd load em, and shoot em! There won't be any difference in pressures, and they just might become your favorite load! I would almost be willing to bet that if you weigh all the bullets you've cast with that mold, you just might find 1gr of difference between a bunch of them!
 
#11 ·
If next casting session you change the alloy a bit, (accidently or on purpose) or your casting cadence they won't weigh 187 grains. Softer alloy will be heavier....harder, lighter. Cast at a different rate or change from a dipper to a bottom pour and they won't weigh the same.

Shape of a bullet can effect pressures but a lot more so when using jacketed bullets than when using cast. The coefficient of friction of a bullet with a greater bearing surface will be higher than one with less bearing surface, thus raising pressure as does the deeper seated bullet that reduces case capacity. Addition of a gas check changes things yet again.

At the level your loading I wouldn't worry about any of it.
 
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#15 ·
I went a head and loaded a box last night and here's the end result. As I couldn't find a published COL for the bullet I kept seating it deeper and deeper until it would chamber correctly. Not sure if that's the best strategy but it made sense to me. I'm pretty sure (and yes I'm new to casting) that the groove at the top of the bullet is where it's supposed to be crimped but that would be a good 250 thousandths deeper which seems like too large of a jump before it would engage the barrel. From what I've learned here recently is that it's best practice to have that distance as small as possible. And as a note for reference, just a little more than half of the bullet is below the mouth of the case......well I'll just put up another picture. The second image is the bullet before I had finished my seating exercise.

Thanks again for all the good info
 

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#17 ·
Grizz,

It's a Lyman mold and I did do a google search that didn't turn up much. Also, the info is for a cast bullet, good point and I guess you can't assume anything when dealing with a novice like myself :rolleyes:. Here's a picture out of my manual.
 

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#18 ·
You'd think Lyman would publish data on a mold that they made, but perhaps it's an older and now out of production mold, the data might be published in an old and now outdated Lyman manual.

I'm a novice myself, I just assumed you were using cast bullet data until I read Sharps response and figured I better ask instead of assuming. We all know what happens when we assume things ;)
 
#20 · (Edited)
Not quite understanding. 311334 is what's in my book and I believe 311332 is what I have. Not home at the moment to double check.
 
#21 · (Edited)
At least half if not more of the molds I own and use have no published data, unless it was published with my data. With time and experience you'll comfortably find a bullet close to whatever you're casting and extrapolate data from it. Another thing to take into consideration is that cast bullets using Lyman #2 or a 50/50, lead/lino alloy are a lot softer than any jacketed bullet, even the Hawk bullets that are annealed dead soft. Consequently pressure doesn't rise as high or as quickly if sensible data is used or extrapolated. You can over load cast the same as jacketed.

As an aside, once ignition of the powder is begun and pressure builds, the neck expands to release the bullet and the bullet begins its journey down the bore, it is sized before the first revolution is completed. It seems to me that undoubtedly there has to be a bit of a pressure spike in that first revolution, you can see it on a graph, but after that everything should return to normal with pressure decreasing as the bullet travels down the bore and the expanding gases can't keep up with the ever increasing volume. That is with correct or close to correctly sized cast bullets. Over loads with jacketed bullets are a horse of a different color.

I believe the Hawk bullets go about 24-25 on the BHN scale and Lyman #2 or lead/lino go about 15 BHN. As per my usual disclaimer I stand willing to be corrected as I'm recalling those numbers from memory. I think the hardest cast go about 22BHN. At any rate you should be fine with your bullets. If in question drop a couple grains and work up....which would be the wise thing to do anyway.

You did fine in finding the COAL. There's easier ways....well, sometimes they're easier....but what you did works just as good and you're correct in your thought about seating close to the lands.

Your bullet looks like it's an old Gould design from back in the Ideal days, before Lyman bought Ideal. They were and are good bullets. I have a 32 cal., 170 gr. bullet mold that's marked just Ideal so that should tell you how old it is....older than my Dad was when he passed away at 85 less than a year ago. That shows how long a mold will last if taken care of. Anyway, a lot of those old bullet styles were carried forward....because they worked....and there is no precise data available for them.

As we all learn more we become more.....flexible(?).....or maybe confident and knowledgeable are better words to use, in our ability to look at the bullet we are using or want to use, the cartridge and rifle we're using it in and published data for similar bullets, cartridges and rifles. Almost always a starting load can be determined. We also learn who may know something about the components and rifle or handgun we're using or want to use and who we believe we can trust to ask. Handloading is sort of like life, it isn't a destination, it's a journey. I've been doing this silly stuff for over 50 years and to me it seems I've learned more in the last 5 than in all the preceding years....and STILL have a long way to go!!!
 
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#23 ·
Alpo, I left the mold at my father's house since that's where I cast. Next time I'm there I'll write down the mold number. Oops :rolleyes:
 
#24 ·
Oh geezzz...I just looked at your picture of the data you're using. You're at 8 grains below max....load fearlessly!!!!
 
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