How far to go before giving up on a powder or bullet and which one?

[mike a]

Nice wave

Sine wave. Don't you people sleep. It's 920pm here, 20 min past my bedtime. I'll be on the range fully setup by 6am. Good nite all. Mike

 

[David Christian]

A good barrel should shoot less than 3/4 MOA with nearly anything you put in it. If not, you are more likely to have a problem other than the load.

I'll just throw this out here:

My theory is that there are 3 kinds of nodes. Lets just call them full nodes, half nodes, and quarter nodes.

If I were to make an analogy, I would equate them to meeting girls.

A quarter node is really attractive, but is in need of constant attention. If you fail to anticipate anything, your dreams won't come true.

A half node is very attractive, but the attention requirements are reduced. You can make up with a half node if you get off track. For a point of reference, at least 3 of the last 4 F-Open national record holders were shooting a half node when they set the record.

A full node is the proverbial "Where have you been all my life?" It requires some attention, but never lets you down. Its bad day is almost as good as the other's good days.

While my calculator isn't ready for prime-time, I can give you a good guess as to which you are looking at. Here is what I need:

Bullet manufacturer, weight, and type I think you said Nosler, but what weight and type?
Case manufacturer and primer
Cartridge - I think you said 308 Win
Charge and chronographed velocity of your best load thus far.
Barrel length

From there, I can give you a good guess of where you fall in the spectrum.

@Keith Glasscock, you are such a player! Nice analogy. Only if we had more ladies in this sport!

 

[JFrank]

Sine wave. Don't you people sleep. It's 920pm here, 20 min past my bedtime. I'll be on the range fully setup by 6am. Good nite all. Mike

Brett never sleeps... me I’m out at 8:00

 

[Bc'z]

Brett never sleeps... me I’m out at 8:00

And when I do sleep I dream of shooting and women, not necessarily in that order.
@Lefty Trigger I've got 100, 155gr lapua scenars my brother gave me. I'll pass them on to you to try if you'd like.
Maybe it's time you try a different bull

 

[Keith Glasscock]

This info was from my first OCW using H4895 powder.
Bullets are Nosler 155gr Custom Competition seated at recommended length of 2.800 which is .008 jump in my barrel (1-12 twist 26" length)
Remington brass with Federal 210m primer
H4895 powder and OCW "velocity flat spot" is 41.0gr at 2743 and 41.5gr at 2749.

A few things I note here. First, you are working an extremely low area of the pressure curve. While some powders may like that, most don't. In fact, you are a full 2 grains below the Hodgdon recommended starting load. That suggests that the ignition might be inconsistent, giving you a "flat spot" that does not appear with a node.

From a node perspective, that load should be nearing a half-node.

It looks like you might have the head room to move up to a full node *if* pressure signs do not develop. There should be a full node around 2890 fps. The velocity will be plus or minus 30 in my experience. I can't realistically give you a charge for that speed, as your previous data is so low pressure that the powder's progressiveness has yet to come into play.

Since your question was initially about AR comp, I would suggest starting by finding the load window. Start at a safe load, and work up until you see the first pressure indication while noting velocities. This is key to knowing where you can safely work. let me know what your charges/velocities are for a few of those and I can help you home in on the area to work.

Be safe,
Keith

 

[dcali]

Personally, it takes me around 80-100 rounds to find and confirm load for a bullet/powder combo. If I don’t see potential within 30-40 rounds, chances are good that it’s just not right. But I do remember a time I shot up about 100 rounds, and struggled to get below .6 MOA, and then on the las two groups it was in the .2s. So it’s really hard to say.

In my experience, changing the powder will matter more than than changing the bullets (assuming high quality bullets). Bullets are pretty constant no matter the rifle- they just spin out the end of the barrel. If you time it right, they work. Powder depends on barrel length, bore friction, etc. I had a box of Sierra 107s thar shot wonderfully with 4350 out of a 6XC. Everyone said 4831 was also worth a shot, so I tried it. Shot terribly. Like 1MOA, no matter what I tried. I don’t know why- it was the same box of bullets. Lots of people said it shot very well for them.

I’m sure there are guys who can tell you the exact opposite - that changing bullets made all the difference. They why’s of this seem to be a mystery.

 

[rogina]

Personally, it takes me around 80-100 rounds to find and confirm load for a bullet/powder combo. If I don’t see potential within 30-40 rounds, chances are good that it’s just not right. But I do remember a time I shot up about 100 rounds, and struggled to get below .6 MOA, and then on the las two groups it was in the .2s. So it’s really hard to say.

In my experience, changing the powder will matter more than than changing the bullets (assuming high quality bullets). Bullets are pretty constant no matter the rifle- they just spin out the end of the barrel. If you time it right, they work. Powder depends on barrel length, bore friction, etc. I had a box of Sierra 107s thar shot wonderfully with 4350 out of a 6XC. Everyone said 4831 was also worth a shot, so I tried it. Shot terribly. Like 1MOA, no matter what I tried. I don’t know why- it was the same box of bullets. Lots of people said it shot very well for them.

I’m sure there are guys who can tell you the exact opposite - that changing bullets made all the difference. They why’s of this seem to be a mystery.

In my opinion it is more important to shoot a bullet that matches your reamer.

 

[Liven The Dream]

Shot a lot of Nosler 155 in my Palma Rifles.
These had 30" & 32" 1-13 &1-12 Barrels.
They liked a .010 Jump . Vol. 2984 -3018 ?
Varget was and is the Powder of Choice ?

One barrel I had lover IMR 4320 ?

 

[Lefty Trigger]

And when I do sleep I dream of shooting and women, not necessarily in that order.
@Lefty Trigger I've got 100, 155gr lapua scenars my brother gave me. I'll pass them on to you to try if you'd like.
Maybe it's time you try a different bull

Thanks I would love to try them, that's a very nice offer and I appreciate the help.

 

[Lefty Trigger]

A few things I note here. First, you are working an extremely low area of the pressure curve. While some powders may like that, most don't. In fact, you are a full 2 grains below the Hodgdon recommended starting load. That suggests that the ignition might be inconsistent, giving you a "flat spot" that does not appear with a node.

From a node perspective, that load should be nearing a half-node.

It looks like you might have the head room to move up to a full node *if* pressure signs do not develop. There should be a full node around 2890 fps. The velocity will be plus or minus 30 in my experience. I can't realistically give you a charge for that speed, as your previous data is so low pressure that the powder's progressiveness has yet to come into play.

Since your question was initially about AR comp, I would suggest starting by finding the load window. Start at a safe load, and work up until you see the first pressure indication while noting velocities. This is key to knowing where you can safely work. let me know what your charges/velocities are for a few of those and I can help you home in on the area to work.

Be safe,
Keith

Ok while I agree with you on the speed being low my reasoning behind it is the fact that with only 300 yards to shoot the speed is not really needed, unless you feel that the speed is a must for performance. I have mostly loaded for the low node because of the distance available to shoot. I also shoot a 6mmBR and get outstanding results with it shooting about 2550 fps and that is about 300-400 fps slower than most load for that round.

 

[Bc'z]

Thanks I would love to try them, that's a very nice offer and I appreciate the help.

Shoot me a PM with your address I'll get them shipped off next week when I drop these stocks in the mail.

 

[Sandstorm]

Nice X-mas gesture there Bc'z ....155 Scenars and a little more powder to push them a little faster I say cant hurt.
I push mine with 44.3 gr Varget and at a 100 there all touching.

 

[Bc'z]

Nice X-mas gesture there Bc'z ....155 Scenars and a little more powder to push them a little faster I say cant hurt.
I push mine with 44.3 gr Varget and at a 100 there all touching.

It's the Accurate Shooter way.
Pay it forward as you can.

 

[Intheshop]

Tough question,and this isn't specific to 308.

If I know from experience that a certain powder has been a solid "go getter".... and for some reason am welded(committed) to it's use then maybe 50 rounds? and then,the bullet is either gonna get massaged or changed somehow.

If it's the other way round..... got to use this particular bullet for whatever reason and am searching for a load amongst say 3 or 4 powders,it's going to take me more time/loads. That's not to say a bughole load doesn't show up quickly changing powders,just that I feel you have to be more patient changing powders,at least in shear numbers downrange,than changing the bullet somehow. Good luck with your project.

 

[Lefty Trigger]

Went out this morning in the cold and tried the AR Comp loads I made up. Groups and numbers went to crap at 40.6 and It might have started to be coming back around at 41.5 but that is where I stopped the charge weights, should I have went on up? The "split numbers" beside the velocity is ES/SD

 

[Bc'z]

Ok while I agree with you on the speed being low my reasoning behind it is the fact that with only 300 yards to shoot the speed is not really needed, unless you feel that the speed is a must for performance. I have mostly loaded for the low node because of the distance available to shoot. I also shoot a 6mmBR and get outstanding results with it shooting about 2550 fps and that is about 300-400 fps slower than most load for that round.

But are you maximizing the bullets fullest potential running at lower speeds?

 

[Lefty Trigger]

That I don't know? Never spent much time working to max figuring whats the point only going 300 yards. Figured it would be easier on the gun, brass and me keeping the loads low. Maybe that's not the best idea? So should I work up to pressure and just back down under that or work for a velocity range?

 

[JFrank]

I work until I flatten off or hit pressure. I run 44.2 with good results. I could go up .1
Yeah I’m a ladder guy

 

[Keith Glasscock]

Looking at your AR comp groups, I came up with a couple of observations.

Your barrel makes a lot more velocity than expected for a 308 with the bullets described. It also is not a linear burn-rate variation. In other words, the burn rate calculated for the top 3 loads is significantly different from that of the bottom 3.

There should be a full node just above the top load shown ~2830-2840 fps. The pressure is up in the normal range at the 41.5 shown, so there shouldn't be any reason that you won't get decent results. BTW, QL predicts that you cannot reach the next higher half node without going too high on the pressure.

With that in mind, the groups do not look right. The 41.5 grain load should be significantly better than it is. If you don't have any pressure signs at 41.5, I'd suggest working the seating depth first. I would move into the case .003" at a step until that group cleans up a bit, then work up a little bit to see if the load settles in.

If the higher load doesn't work out, there should also be a half node ~2730. However, your target is not saying that. The POI is moving in that area. If I use the burn rate from the upper loads, the half node would be at your 39.7 load where the target does say that the load is happier. The pressure there is predicted to be right about 50kpsi, so it is in the mild range for what I would normally recommend.

I see some promise in that powder and bullet. I'd work with it for another 50 rounds before giving up.

Merry Christmas!

 

[Lefty Trigger]

Looking at your AR comp groups, I came up with a couple of observations.

Your barrel makes a lot more velocity than expected for a 308 with the bullets described. It also is not a linear burn-rate variation. In other words, the burn rate calculated for the top 3 loads is significantly different from that of the bottom 3.

There should be a full node just above the top load shown ~2830-2840 fps. The pressure is up in the normal range at the 41.5 shown, so there shouldn't be any reason that you won't get decent results. BTW, QL predicts that you cannot reach the next higher half node without going too high on the pressure.

With that in mind, the groups do not look right. The 41.5 grain load should be significantly better than it is. If you don't have any pressure signs at 41.5, I'd suggest working the seating depth first. I would move into the case .003" at a step until that group cleans up a bit, then work up a little bit to see if the load settles in.

If the higher load doesn't work out, there should also be a half node ~2730. However, your target is not saying that. The POI is moving in that area. If I use the burn rate from the upper loads, the half node would be at your 39.7 load where the target does say that the load is happier. The pressure there is predicted to be right about 50kpsi, so it is in the mild range for what I would normally recommend.

I see some promise in that powder and bullet. I'd work with it for another 50 rounds before giving up.

Merry Christmas!

Should mention that test above was shot at 200 yards and the barrel is a 12 twist. It's kind of a low round count on a new barrel as well and it may speed up a little more. This is also my first carbon steel barrel as everything I've run in the past has been stainless. That's one of the weird things I have seen,... the speed. Some powders run fast like this one and others seem to run slower than expected? These findings can be very frustrating when trying to figure these things out, not getting expected results. I gave up on the .308 round way early this summer and sold my 308 barrels because it had me flustered, this new one still has!