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High pressure help
- Thread starter 1stmar
- Start date
According to hornady the one shot lube is powder safe. And it is a lubricant as shown by the fact that you can size cases with it.
I would be interested to see the results of spray some on a little pile of powder and letting it sit, see if it causes any clumping or adhesion of the powder.
I remember reading about someone who did some testing with spraying the bullets themselves before seating with hornady 1 shot. As i remember it reduced seating force and improved sd/es.
Personally i dry tumble in walnut after sizing to get the lube off. I dont like slippery cases. Plus the stuff is pretty unhealthy if you read the msds, some of the chemicals can kills fish and make you infertile.
I would be interested to see the results of spray some on a little pile of powder and letting it sit, see if it causes any clumping or adhesion of the powder.
I remember reading about someone who did some testing with spraying the bullets themselves before seating with hornady 1 shot. As i remember it reduced seating force and improved sd/es.
Personally i dry tumble in walnut after sizing to get the lube off. I dont like slippery cases. Plus the stuff is pretty unhealthy if you read the msds, some of the chemicals can kills fish and make you infertile.
BandeauRouge
Moderator
all glues contain a solvent.. particularly for high end glue. Used to work on a boot and shoe lines for wolverine making boots and shoes for military contract.
We used a silicone based glue that was roughly 30% methel ethyl ketone, a solvent, and 20% acetone, a solvent. That was so the glue would stay semi liqoud during shipment and before usage. Nasty stuff. if you put an inch into our brush buckets that were filled with pure MEK, after 20 minutes it would be like rubber cement in the bottom
We used a silicone based glue that was roughly 30% methel ethyl ketone, a solvent, and 20% acetone, a solvent. That was so the glue would stay semi liqoud during shipment and before usage. Nasty stuff. if you put an inch into our brush buckets that were filled with pure MEK, after 20 minutes it would be like rubber cement in the bottom
Everything liquid contains a solvent. That's basic high school chemistry. Even water is a solvent, and used to be called the "universal solvent" because it dissolves so much different material.
Any, and every paint, glue, or other compounds that contain a carrier that evaporates contain solvents.
Hexanes are a chemical family that uses a specific chemical bond pattern. ALL the chemical compounds using that pattern are "hexanes" but can be widely different in their effects depending on the specific elements and combinations making up the compound.
Hexanes, heptanes, peptanes, octanes, along with many other "-anes" and "-ides" and "-ites" and "-ates" and many other terms are terms identifying chemical compound formulations and construction, and by themselves don't tell you much about what any specific compound is, or does.
Any, and every paint, glue, or other compounds that contain a carrier that evaporates contain solvents.
Hexanes are a chemical family that uses a specific chemical bond pattern. ALL the chemical compounds using that pattern are "hexanes" but can be widely different in their effects depending on the specific elements and combinations making up the compound.
Hexanes, heptanes, peptanes, octanes, along with many other "-anes" and "-ides" and "-ites" and "-ates" and many other terms are terms identifying chemical compound formulations and construction, and by themselves don't tell you much about what any specific compound is, or does.
Military brass is generally heavier and lower capacity inside than commercial, so commercial load data being off with it isn't a surprise.
If you seat a bullet out to touch the lands, pressure increases about 20% over typical data numbers. As you seat it incrementally deeper, that pressure drops, but only so far. As you go deeper still, it starts to rise again because the bullet is shrinking the powder space, increasing confinement. I think you are correct that the boattails are eating up too much space, and you simply need a smaller charge with them. Bullet weight alone doesn't determine the charge requirement.
Did your chronograph not reveal a velocity difference?
If you seat a bullet out to touch the lands, pressure increases about 20% over typical data numbers. As you seat it incrementally deeper, that pressure drops, but only so far. As you go deeper still, it starts to rise again because the bullet is shrinking the powder space, increasing confinement. I think you are correct that the boattails are eating up too much space, and you simply need a smaller charge with them. Bullet weight alone doesn't determine the charge requirement.
Did your chronograph not reveal a velocity difference?
I did not see a velocity difference between the hornady 165 42.5gr 4064 and the Sierra 168smk 42.5. They were both 2500-2550 out of my M1A scout. The highest of the last batch of 20 was the high pressure round at 2569. It had the shortest COL.
Agree on the military being lower case volume hence the 42.5 filling the case up to the neck and possibly creating a compressed load in comparison to the 168. My COL varied much more without the h1s. This variation coupled with the flat base and smaller case volume probably was root cause.
Agree on the military being lower case volume hence the 42.5 filling the case up to the neck and possibly creating a compressed load in comparison to the 168. My COL varied much more without the h1s. This variation coupled with the flat base and smaller case volume probably was root cause.
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Interesting. The old load for Federal Gold Medal Match ammunition using the 168-grain Sierra MatchKing was 43.5 grains of 4064, and the velocity from a 24" SAAMI type velocity and pressure barrel was 2650 fps. Of course, this was in Federal brass that weighs about 10 grains less than some of the military stuff I've had. I don't have an exact water capacity comparison, though. Weight alone won't tell you because of the dimensional tolerances around things like the extractor groove depth and relief angle that can cause weight to vary without affecting interior capacity. Also, the 4064 they used must have been made especially for them with tight relative burn rate tolerance, as the load stayed the same over decades.
BandeauRouge
Moderator
Have seen older reports online from 10-20 years ago that showed that the case weight between "military" and "civilian" .308/7.62x51 brass was not correlated to the cartridge head stamp.
Some civie brass weighed as much as the spec for military brass, some military brass weighed less then civilian brass. Some times it simply depended on if the military brass was made by a company that made military contract ammo.. and so on.
Some civie brass weighed as much as the spec for military brass, some military brass weighed less then civilian brass. Some times it simply depended on if the military brass was made by a company that made military contract ammo.. and so on.
It's a generalization based on Remington and Winchester both being lighter than LC and IMI and most other boxer-primed military brass (there's some Berdan-primed brass that's lighter). I've even seen some foreign stuff as heavy as 189 grains. Starline weighs what the military stuff does. Lapua and the Federal .308 match brass that I've looked at is at more like 172 grains. Remington is typically in the 166 to 168-grain range. I've got Winchester as low as 153 grains, but more recently, they've been a bit closer to Remington. Anyway, the OP is using LC brass, specifically, and it is heavier than the Federal match brass I've weighed that uses the 43.5-grain load, and Hodgdon says 45.9 grains is fine in the Winchester brass they use. The OP would have some serious pressure signs with that, I imagine.