My .308 gas gun has a relatively short barrel and I’m trying to get some velocity back by mimicking MK319 mod 0. Issue is I’m looking at N133 and IMR 3031, N133 has a max load with my bullet of 39gr while IMR is at 44. Other forums people are loading it was 44gr of N133 with no signs of over pressure. Just trying to make sure I don’t blow my gun up.
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Trying to develop a safe load for my .308, need help
- Thread starter MichaelP776
- Start date
Not enough information.
What bullet?
What rifle?
What barrel length?
What is your velocity objective?
What bullet?
What rifle?
What barrel length?
What is your velocity objective?
Some questions:
Barrel length?
130gr SOST bullets?
Brass H20 capacity?
Beyond looking at the top of the primer and case head, look at the primers decapped from the brass and measure the primer pocket size. If your primer pocket is measuring over .2095" from the first firing you are too hot regardless any other non signs of over pressure.
Barrel length?
130gr SOST bullets?
Brass H20 capacity?
Beyond looking at the top of the primer and case head, look at the primers decapped from the brass and measure the primer pocket size. If your primer pocket is measuring over .2095" from the first firing you are too hot regardless any other non signs of over pressure.
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Barnes 130 tsx, FAL, currently 16” will pin and weld a 14.5” over the holidays. I’m trying to mimic the MK319 mod 0 load of 3000 out of a 16”
I’ll have to check the H2O capacity, but it’ll be from a 14.5” barrel, aiming for a velocity of 2850 or so from that length with a 130gr
I looked up the MK319MOD0
I think you could get 2775-2800 from a 14.5" with a 130gr TSX. Brass primer pockets might not last long.
- 130 grain OTM (reverse draw jacket) bullet
- Temp stable flash reduced propellant
- Not yaw dependant
- Reduced recoil (10%)
- Optimized for MK 17 (16” BBL)
- 2925 fps @ 15’
- Accuracy, combat -NTE 2 MOA. (600 yds)
- Intermediate barriers; auto glass/doors.
- Terminal, Specifically CQC & behind barriers
I think you could get 2775-2800 from a 14.5" with a 130gr TSX. Brass primer pockets might not last long.
Well, that seems to be asking a lot from that length barrel.
Looks to me like Win748 is your best powder alternative for "relatively" safely reaching that velocity.
My data is based on 50.392 grain H2O case, so your case volume will matter.
With N133 at 100% case fill you are only looking at 2550-ish. So, with either load it will be compressed.
Not sure you're going to "safely" get there with the powders you've listed, based on my cursory look at the data, without going dangerously close to the edge of what is safe.
Looks to me like Win748 is your best powder alternative for "relatively" safely reaching that velocity.
My data is based on 50.392 grain H2O case, so your case volume will matter.
With N133 at 100% case fill you are only looking at 2550-ish. So, with either load it will be compressed.
Not sure you're going to "safely" get there with the powders you've listed, based on my cursory look at the data, without going dangerously close to the edge of what is safe.
Thank you, I’ll have to try it out. Right now I do need to chrono my factory M80 ball though because I think I’m getting way higher velocity out of the 16” than I was thinking I should. My math for my holds isn’t adding up because holding at 2.5 mile like my math is showing is sending them over it holding dead on works so my rifle might be sending stuff way higher velocity than I thought for M80’s
Thank you, I wish I could just get the factory ammo but the supplies seemed to have dried up a while ago
Try running the number with 54gr H2O. That would average out over the multiple brands I've tested over the years.
The cases I’m using are LC, Boxer primed Hirtenberger, and RUAG. So I’ll have to measure all of those
Using that case volume it looks like I can get to 2725-ish with N133, but it isn't a load I'd be comfortable shooting.
Hold on, looks like 3031 is possible, but I'm not comforatable posting the numbers here.......Something I'd also not be comfortable shooting and would have to start much lower and work up to.......But I got 2846 at just below max pressure with 3031.........AND you are burning just over 99% of your powder.
So, OP, I'd say stick with 3031 and work your way up safely, monitoring velocity and watching for signs of pressure. But you're not likely to get there with published load data.
Barnes has posted on their website a decent load with 3031 for this round so I might try that. Was wanting to do N133 because I’m pretty sure it has flash suppressant in it
The Barnes published 3031 max load data should put you really close to where you want to be.......velocity wise. Just be safe.
Thanks, I’m just surprised by the one laid i saw online of someone using 44gr of N133. I might try to ask some guys from AMU if they have the actual load data for the production round
I think N135 would allow more velocity before pressuring out in comparison to N133. I've tested N135 in 5.56, 708 & 308 and its killing it!
That load "could" be perfectly safe in your rifle, depending on your case volume and your chamber. However, its only likely to get you to 2685-ish.
FWIW my initial case volume was a statistical average of LC12 762 brass in my inventory.
You shouldn't simply have a velocity in mind when developing a load, particularly with those short length barrels that you mentioned IMHO.
Find something that shoots accurately in your firearm. 1-300 fps is not going to make a substantial difference at the distances you will likely be shooting.
Just my humble Saturday morning opinion. Good Luck
Find something that shoots accurately in your firearm. 1-300 fps is not going to make a substantial difference at the distances you will likely be shooting.
Just my humble Saturday morning opinion. Good Luck
I’m more worried about terminal effects than pure accuracy. The majority of my ammo is surplus M80 ball and overall I’m not planning on shooting this rifle off of bipod or tripod and rarely off of a bench except for when I’m zeroing.
I'm definitely not an expert at reloading but three things comes to mind.
*Use a powder that will get the velocity you need instead of trying with some that doesn't.
*Why 'pin and weld' a shorter barrel to make legal rifle lenght instead of just leaving it? Especially since you're chasing velocity and not willing to make it an SBR...
*When pushing the envelope of charges beyond published max (which are easily found in any reloading manual and online - Hodgon is great for that!) be VERY careful, slow and extremely accurate with collecting ALL possible data, and look over everything, twice!
(and, obviously, when doing anything outside safe/known load development meassure YOUR velocity.)
*Use a powder that will get the velocity you need instead of trying with some that doesn't.
*Why 'pin and weld' a shorter barrel to make legal rifle lenght instead of just leaving it? Especially since you're chasing velocity and not willing to make it an SBR...
*When pushing the envelope of charges beyond published max (which are easily found in any reloading manual and online - Hodgon is great for that!) be VERY careful, slow and extremely accurate with collecting ALL possible data, and look over everything, twice!
(and, obviously, when doing anything outside safe/known load development meassure YOUR velocity.)
This kills me, but it's only my job to recommend, not question a guy's project.
I agree, just looking at things from a logical standpoint. I've never understood the whole 'ad stuff to a short barrel to make it legal lenght' vs. just leave it, since it will physically be the same length so no gain in mobility, or make it the lenght you want either legally, or not...This kills me, but it's only my job to recommend, not question a guy's project.
With a 12" drop tube, vibrator, and still crunching kernels. Never get consistent bullet seating with compressed cases like this.
AA2520 works great with my 137 Hammers at 49.5gr and fits nicely. So a 130 TSX should have even more room!
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The reason I’m doing a pin and weld is because I’ll be suppressing it. It currently has a metric threaded pencil barrel on it and the suppressor muzzle device I had on that wouldn’t sit concentric and destroyed one can already. Im rebarreling to a medium contour barrel and having it threaded to a standard pitch but with the suppressor I want to put on it it’ll benefit by having a shorter barrel so I don’t have a rifle too too long for normal use
Will taking 1.5" off the barrel really make it handier.
I am having great results with 2000mr but its from an 18, 20 and 24" assortment of barrels. The velocities are, on average, 135fps faster than equivalent varget
The powder you will get the highest velocity from is almost certainly going to be a dense, high energy double base powder. Single base stick powders won't get you there.
2000 MR is the best choice for maximum velocity, but it generates a ton of gas in semi autos and isn't the easiest on barrels.
Your velocity goal of 3000 fps is unrealistic, particularly in a 14.5" barrel. Somewhere around 2700-2800 is about the most you should actually hope for.
Also I wouldn't hold your breath for amazing accuracy from your FAL. Mine was a consistent 3-3.5 MOA gun even with high quality match handloads, and it chewed up brass like crazy even with the gas adjusted correctly.
2000 MR is the best choice for maximum velocity, but it generates a ton of gas in semi autos and isn't the easiest on barrels.
Your velocity goal of 3000 fps is unrealistic, particularly in a 14.5" barrel. Somewhere around 2700-2800 is about the most you should actually hope for.
Also I wouldn't hold your breath for amazing accuracy from your FAL. Mine was a consistent 3-3.5 MOA gun even with high quality match handloads, and it chewed up brass like crazy even with the gas adjusted correctly.
What is the point of mimicking the load as per OP?
Sounds like a PITA and the gun doesn't even mimic the firearm intended for the load.
And why do we need flash suppressant if we’re shooting w a can?
Sometimes it’s more useful to help a guy with his goals themselves rather than their fulfillment
Sounds like a PITA and the gun doesn't even mimic the firearm intended for the load.
And why do we need flash suppressant if we’re shooting w a can?
Sometimes it’s more useful to help a guy with his goals themselves rather than their fulfillment
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He's not concerned with accuracy, just terminal performance.
The projectile has to work, even if he doesn't hit the intended target...
^^^^^ let all that sink in.
Guys, just keep hitting your head with that hammer.
It'll feel really good when you stop.
The projectile has to work, even if he doesn't hit the intended target...
^^^^^ let all that sink in.
Guys, just keep hitting your head with that hammer.
It'll feel really good when you stop.
The gun it is designed for is a 13” scar 17. The load is designed for 2700 out of that length scar. And the suppressor is still currently in ATF jail so I’d like for it to be as low flash as I can for now
I’m not looking for a sub MOA round or anything, I know that accuracy for the load isn’t really needed due to the inherent inaccuracy seen in tilting block firearms. I would be more than happy with it shooting 2.5 MOA which would allow me to hit a man sized target at a little over 700m. As long as the round is as accurate as factory ball ammunition it is fine for my needs
I’m not sure how much handier it will be but with me already destroying one suppressor I want the mount to be on their solidly and it’ll add an additional 6” past the muzzle so it won’t hurt
What is the logic behind thinking that barrel length is the issue causing baffle strikes?
have you seen this?
www.ar15.com
MK 319 Mod 0 Load Data Inside - AR15.COM
Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear.
www.ar15.com
Nobody can be faulted for having not seen anything on AR15.com.have you seen this?
MK 319 Mod 0 Load Data Inside - AR15.COM
Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear.
It’s not the barrel length but that I’m going to pin and weld either way to make sure I don’t cause another strike so I might as well do a 14.5 over 16 since I’m pinning and welding either way
Yes I saw it but their load is 5 grains over the manufacture recommended maximum so I thought I’d ask here insteadhave you seen this?
MK 319 Mod 0 Load Data Inside - AR15.COM
Firearm Discussion and Resources from AR-15, AK-47, Handguns and more! Buy, Sell, and Trade your Firearms and Gear.
And I’m cutting it down from a 21” barrel anyways since they don’t make 16” barrels for a medium contour with the gas system I need
Hodgedon H335 might be worth a try for a couple of reasons. It works well with light .308 bullets (147 to 155) and because this powder is on the fast end of the spectrum, it was the only powder to reliably cycle a new FN FAL build during its initial break-in. I still use it now in the FN at 41.5gr with the 147gr bullets. Since the OP wants a short barrel gas gun, this powder might provide a burn rate to keep velocities on the higher than normal side.
Easy, easy!
Those guys are blowhards, but there are several who know their stuff (especially about AR15 family) as well or better than anybody.
But I agree, and I'm not a member there for a reason. Blowhards and Chest Thumpers and Knuckle Dragging Mouth Breathers
So a bit of an update, I talked to one of my buddies who’s got contacts at both sniper school and the army marksmanship unit which are just down the road here. I got the official load data for this round and it’s using a way faster powder than I initially thought but this is the published load data for the round and looking at factory data and pressures it seems reasonable.
