For me, the biggest reason that I changed was that the Hornadys are aluminum (relatively soft) and the SAC's are stainless (much, much harder).
And, I'm at the age where I want nice/good stuff. SAC fits that bill nicely.
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.308 Winchester
- Thread starter Two Shoes
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And, I'm at the age where I want nice/good stuff. SAC fits that bill nicely.
I just measured the BTO of my 168 and 175 SMK's and there was a .002 difference, the 168 being the longer. BUT. . . . keep in mind there can be a MUCH bigger difference within a lot AND an even bigger difference between lots (like .034"). So, that .002 difference really doesn't help you. Add to that, there's variations in different comparators.
I've measured and shot a lot of 168's and 175's. For the most part, the difference in BTO between the two tends to be small.
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You might think about trying the 169 SMK's??? The 169 SMK BTO's are ~.020 longer than the 168 SMK's and the COAL is about .105 longer. The 169's are tipped and works really well out to 1000+ yds . . . better than the 175's. They can be a little hard to find, but they're out there:
Sierra .30 Cal 169 Gr MatchKing Bullets
Sierra .30 Cal 169 Gr. HPBT MatchKing Bullets This bullet was designed with one thing in mind, and that was to shoot 1000 yards in a 308 Winchester. To accomplish that, Sierra added length to the boattail and engineered a forgiving tangent ogive with a closed nose. Doing this gave it a .527...
www.creedmoorsports.com
Oh I know all about them. It was the first bullet I tried in the rifle in January with H4895 and it shot lights out, even jumping .117 at mag length, better than any M1A I've ever had, and was still shooting great up until about a month ago with that bullet until I changed lots of powder and the accuracy has gone to shit. Have tried everything, re-working up the load, seating depth changes, cleaning the gas system, barrel, different torque specs on the gas plug, yet the groups are inconsistent and all over the place. Even tried some Federal GMM that I know shot well and it still shoots so I figured I would try a different bullet and powder.You might think about trying the 169 SMK's??? The 169 SMK BTO's are ~.020 longer than the 168 SMK's and the COAL is about .105 longer. The 169's are tipped and works really well out to 1000+ yds . . . better than the 175's. They can be a little hard to find, but they're out there:
Sierra .30 Cal 169 Gr MatchKing Bullets
Sierra .30 Cal 169 Gr. HPBT MatchKing Bullets This bullet was designed with one thing in mind, and that was to shoot 1000 yards in a 308 Winchester. To accomplish that, Sierra added length to the boattail and engineered a forgiving tangent ogive with a closed nose. Doing this gave it a .527...www.creedmoorsports.com
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Anyone have any experience with N140, Lapua cases, and SMK 169? I’ll be shooting out of a 24” MRAD. I was going to use the 168s for 600 and under, 169s for up to 1k (hopefully) and 338 Lapua for greater than 1k
Thank you! I only have the newest Hornady manual and I was afraid the VV may not have the 169 data and I wasn’t sure how close the 168 would be. I greatly appreciate it sir!
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I don't have any direct experience with that, but I don't see any reason why it might not work for you.
Your velocities most likely will be different from what here:
Different torque on the has plug ? That has that much effect on the m1a ? Interesting. My brother has one.
Just finished fire-forming my reformed SIG 6.8x51 Hybrid military cases. Got some new tear down cases with primers still in them for SUPER cheap. I reformed them Friday night, and then loaded them up yesterday. Went and shot them today, and will clean and polish them when I get ready to run another batch of brass in the US cleaner and tumbler.
Here they are after pushing the shoulders and necks back and reforming them for .308 Win. It's not a simple 1-step process to avoid the donuts or getting lube dents in the necks, so you have to use a body die and size down the case, then mandrel the necks to .30 caliber, and FL size them.
Here they are after pushing the shoulders and necks back and reforming them for .308 Win. It's not a simple 1-step process to avoid the donuts or getting lube dents in the necks, so you have to use a body die and size down the case, then mandrel the necks to .30 caliber, and FL size them.
I lube inside necks, then mandrel up first.
Size with the FL sizing die, don't lube where the neck is being formed.
Neck turn, and body die.
No dents, no donuts.
Here is the lathe neck turning operation.
It cuts the full 20° angle of the 308, but notice the sharp angle at the neck / shoulder junction. This takes away donut material.
Here is a loaded 308 win 215 gr Berger from the neck turned case.
A better close up of losing the donut.
This formed 338 RCM case necked from 6.5PRC ...note the neck/ shoulder junction sharper angle of the newly formed 338 RCM against the factory 6.5 PRC.
I always cut it completely, neck, radius and shoulder angle...cause I have a lathe.
But hand neck turned into the shoulder will accomplish most of what is needed.
Size with the FL sizing die, don't lube where the neck is being formed.
Neck turn, and body die.
No dents, no donuts.
Here is the lathe neck turning operation.
It cuts the full 20° angle of the 308, but notice the sharp angle at the neck / shoulder junction. This takes away donut material.
Here is a loaded 308 win 215 gr Berger from the neck turned case.
A better close up of losing the donut.
This formed 338 RCM case necked from 6.5PRC ...note the neck/ shoulder junction sharper angle of the newly formed 338 RCM against the factory 6.5 PRC.
I always cut it completely, neck, radius and shoulder angle...cause I have a lathe.
But hand neck turned into the shoulder will accomplish most of what is needed.
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Fart wrong and it will have an effect on an M1A. One day it will shoot great groups and the next day it won't, very frustrating rifle. Yet I can't live without one.
A lot of the armorers from the 70's and 80's had some very interesting things to say about the rifles and what their shooting teams discovered. Gas plug torque, swapping out gas pistons and altering the dwell time by removing material from the plug or piston was all part of trying to squeeze every last bit of accuracy out of them. Problem is, you can waste a lot of time and ammo trying to figure out what combination of those, if any, would even show up on paper with any consistency.
I would love to have one of those guys at the range with me when I'm testing loads.
I've experienced some of the inconsistency with my brothers rifle. I think I've shot it more than he has.
A good friend of mine used to shoot service rifle matches and built match grade m1a's and garands. He was a wealth of knowledge when it came to the tricks to make an m1a shoot. His match rifle is for sale at the moment. If I can scape the funds together I'm going to buy it.
I shoot a lot of 5 shot groups with 4 touching and then one a half to three quarters of an inch away from the group. If I ever figure out how to tune that out, I'll let you know.
It's usually never the 5th shot. Usually 2nd or 3rd and then all remaining shots cluster back into the group.
I am trying to determine the best OAL for my rifle and am wondering if there is a recommended gap off the lands. Using the Hornady OAL gauge the total OAL is 2.94 in. Should I back it off .02?
Just so there's no confusion. . . Hornady's OAL Gauge is actually used to measure CBTO (Cartridge Base to Ogive) to find where the bullet it touching the lands. OAL is usually a reference to Over All Length.
I assume with you say "OAL is 2.94" you're talking about CBTO, where it's touching the lands???
No, I wouldn't start at .002" if that's what you mean. .020" off the lands to start is just fine. When closer than .010" to the lands, there tends to me substantial pressure spike effecting velocity. This could be an issue as the throat erodes, changing velocity enough to see on target. Therefore, I find it's best to start load development at .010 off the lands and move back incrementally to find a spot that produces the best results.
If one is limited to feeding from the mag, then that COAL (Cartridge Over All Length) for the mag is the place to start the load development.
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I guess I used the wrong terminology. Not using the mag, just single feed.
When powder manufacturers list a load amount for a particular round are they using a cartridge made for a magazine? How would the load amount change with a longer CBTO? I'm new to this so it might not make sense.
When powder manufacturers list a load amount for a particular round are they using a cartridge made for a magazine? How would the load amount change with a longer CBTO? I'm new to this so it might not make sense.
When you look at powder manufacturers page of data, how the cartridges are loaded is usually listed at the top along with COAL (C.O.L.) with the barrel length (often 24") for velocity reference purpose. They do not list CBTO since everyone's chamber can have a very different freebore and different comparator inserts have various diameters. Like what you see here on Hodgdon's website.
So back to my question. If the bullet is extending further into the chamber and leaving more room in the cartridge can the powder load be increased safely?
To a degree yes, but you have to work up the load and check for pressure. The closer you get to the lands, the more pressure increases.
Yes. But when doing that you'll want to do it in small increments, starting well below the powder company's maximum recommendation (like ~10% below) and monitor for pressure signs as you increase powder charges.
Pressure signs:
-Stiff bolt lift
-Ejector swipe
-Ejector imprint
-Primer cratering (though some "cratering" is more from primer flow into excess space around firing pin)
FYI: the further you seat the bullet into the case the faster the powder burns creating a sooner release of the bullet letting gasses blow past the bullet before it's fully engraved. At the same time the increase in seating depth makes for a larger chamber volume for the blowby gasses to fill, which tends to reduce velocity a little. When you get closer to the lands, like less than .010" that chamber volume is small and tends to spike the pressure. Here's an example how that pressure curve works:
I got a great deal on a bunch of 168 ELDM’s. I usually shoot the 178’s and have had great results with Varget and Staball Match.
Any other suggestions out there worth trying?
210’s primers
24” 1/11
Any other suggestions out there worth trying?
210’s primers
24” 1/11
Varget and the 168 ELDs is a great combo. One I use in my match rifle.
In case you’re not aware, you will likely need to reduce your load in your gas guns from your bolt guns to avoid potentially dangerous pressures.
I never jam bullets into the rifling. That causes a big pressure spike of about 10,000 psi...plus if you unload it the bullet can stick on the barrel, making a big powder mess in the chamber and down the barrel.
Bullets have a variation on the ogive or radius of the point...some are better than others, and can change from lot to lot.
I am usually backed off .006" as close as I ever get but sometimes much more.
A long jump doesn't matter if the bullet don't care...shot some tiny groups with long jumps.
One can slowly add a fraction of a grain of powder for alot of extra COAL. Until ya hit the lands then the big pressure spike.
So if your looking for accuracy I wouldn't recommend adding powder above the max load, at longer than normal COAL for that cartridge but stay with book max requirements, until one has lots of experience and many thousands of rds down range.
Autos and bolts can take the same load....IF the AR is not one of those in the 6 ARC, Grendel, Valkyrie, Bushmaster, etc low pressure cartridges, weak and thin steel bolts, requires you keep the pressure down.
And IF your boltgun pressures are not quite a bit over max...as many are.
I shoot the same loads in 308, and 5.56 in boltguns as in ARs ...with normal pressure loads, even at book max, and a few +P.
Ya can't just seat a bullet out long and get performance with Varget, it's a good target powder, but not a performance powder, for maximum velocities these days. The magic ain't there, for super high velocity 308 loads.
And a 1/2 grain of powder will not net much more velocity as the extra space has to be filled with propellant gas and still stay inside pressure limits...not worth the squeeze, or worry.
Plus super high velocities are not needed for most shooting endeavors, at moderate to medium ranges...or a few excursions to 1000yds.
Bullets have a variation on the ogive or radius of the point...some are better than others, and can change from lot to lot.
I am usually backed off .006" as close as I ever get but sometimes much more.
A long jump doesn't matter if the bullet don't care...shot some tiny groups with long jumps.
One can slowly add a fraction of a grain of powder for alot of extra COAL. Until ya hit the lands then the big pressure spike.
So if your looking for accuracy I wouldn't recommend adding powder above the max load, at longer than normal COAL for that cartridge but stay with book max requirements, until one has lots of experience and many thousands of rds down range.
Autos and bolts can take the same load....IF the AR is not one of those in the 6 ARC, Grendel, Valkyrie, Bushmaster, etc low pressure cartridges, weak and thin steel bolts, requires you keep the pressure down.
And IF your boltgun pressures are not quite a bit over max...as many are.
I shoot the same loads in 308, and 5.56 in boltguns as in ARs ...with normal pressure loads, even at book max, and a few +P.
Ya can't just seat a bullet out long and get performance with Varget, it's a good target powder, but not a performance powder, for maximum velocities these days. The magic ain't there, for super high velocity 308 loads.
And a 1/2 grain of powder will not net much more velocity as the extra space has to be filled with propellant gas and still stay inside pressure limits...not worth the squeeze, or worry.
Plus super high velocities are not needed for most shooting endeavors, at moderate to medium ranges...or a few excursions to 1000yds.
Yeah man, Varget and 178's have been great. Varget around here is getting spendy though. I think a one #'er was like 69 bucks at my local vs StaBall Match at 54.
Side note, and this may be a dumb question, but I got to thinking about bumping the .002/.003 shoulder off of fire formed practice. So, should all fire formed brass, regardless of brand, reloaded, factory, etc. be the same size to the same rifle in theory? In other words, how are you benchmarking what you are subtracting from? I'd imagine an over-pressured load vs a typical factory load could/would cook off and stretch differently, or is it all the same when it comes to brass heating up and stretching out in a blink. Does one get an average of 5, or is this totally dependent on specific brass? Does this make any sense? lol
Last, what's more important to get right, the case size or OAL sneaking up on the lands? Both? Is it all "test and learn"
Where I'm coming from is I've been reloading for a little while, but it's been pretty much to SAAMI. Would like to see if this makes a meaningful difference.
Check out some of the VV powders. They are cheaper and work well.
You are way overthinking it. You will be using the same brand of brass as if you aren't then you aren't loading precision rifle ammo. Doesn't matter if the brass was fired as a factory load or you loaded new brass. You measure the shoulder of the brass of the fired cases and subtract .001-002". Measure a few cases and work off the shortest one but they should all be very close as within .001".
You should be measuring the shoulder and the OAL and jump off lands, which .020" is a good place to start.
I recently purchased some reconditioned brass brand name-Topbrass. Anyone have any experience with this brand? I looks nice and the bag says it has been sized, cleaned etc. I noticed as I was resizing the neck small clippings of brass were coming off. I know they have not been annealed. Any input regarding quality or what I need to watch for is appreciated.
Then its lake city brass manufactured in 2015.
What we don't know is if it was fired out of machine guns. It probably was.
It'll make alright ammo for plinking.
