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

[Bc'z]

Looking at alliants data for a 308 win you should be able to safely reach 43gr of powder.
Looking at your OCW I notice the scatter of your 40gr charges.
41.5 is starting to come back together, makes me curious as to what's on the other side 41.8, 42.1.
As Keith stated, you might work on seating next then look into higher charge weight.

To answer your previous question, yes I run the highest velocity possible without compromising accuracy.
Maybe run your numbers on Berger's ballistic calculator to confirm stability.

 

[simo hayha]

Try 155 smk on top h4895.

 

[dgeesaman]

This is what I’m doing. I’m sure it could be better but it makes sense to me.

The primary variables are powder charge and seating depth. I start with 25 rounds going through charge weight and then choose a powder weight by OCW or positive compensation reasons. Then I do 25 rounds for coarse seating depth. If I see something good I’ll do 25 as a fine seating depth test. If nothing good, then I take the best seating depth and run another round of powder charges against it.

At this point I’m up to 75 rounds and three tests. Then I move on if it’s not a great load.

I’m sure that loading at the range using a very well sorted setup can get it done quicker. My shooting abilities are less perfect so I don’t want a flyer or two cause me to choose a poor tune.

David

 

[Janson]

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.

 

[Janson]

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.

Can you tell me what other problems besides the load might be

 

[Keith Glasscock]

Can you tell me what other problems besides the load might be

Before we talk about all the things you need to check on your rifle, having the wrong bullet can make even the best rifle shoot poorly. Good bullets with a good track record are needed for this assessment. Try a different one before giving up on a barrel. Hint: There is a lot of BS (claiming they are good) on the internet about certain bullets that really don't group well consistently. I'd recommend something like a Sierra SMK or a Berger Hybrid (old style ones, not the newer long-range ones) to do a rifle check. It can be eye opening!

Let me toss you a few rifle problems that I see from time to time while trying to help other shooters (not a complete list of ways to make a rifle shoot poorly):

Firing pin spring weak/worn out or drag in the ignition system
Scope Rail/Rings/Mounting movement (separate rails on factory actions are a real problem area)
Bedding (mostly if it's loose)
Bad barrel
Loose barrel (unfortunately quite common)
Bad Scope

One last thought about loads - Wrong primer (especially with larger cases and SRP)

Hope this helps

 

[searcher]

I have dialed in a load a load in as little as 30-40 rounds - but have had to switch powders and bullets numerous times to get what I wanted other times. To answer your question as to when to give up on a particular bullet or powder, the way I do it would "usually" have me expend no more than about 60 rounds on one or the other. If the gun likes the powder, you are going to see that in all groups - not just one where you changed the seating depth a few .000", etc.. If I'm getting significantly large groups with a quality target bullet, I change powders. Substituting bullets (of the same weight) doesn't usually shrink bad groups to fantastic groups, nor does a tweak in neck tension or seating depth. While they all work together to tune, they seldom make a bad load shoot.

I have learned to not spend hundreds of rounds (or a thousand...) trying to tune a powder (or bullet) to a gun that it isn't loving. Hopefully your gun agrees with the A/R Comp. If not - find someone to swap out with another powder or, if you are lucky - another bullet of a different weight will work. I have a particular 6 BR barrel that will only shoot one weight of bullet well, regardless of manufacturer or powder used, which is an anomaly. I won't even post how many rounds that took to find it. Most sane shooters would have given up on the barrel.

 

[209jones]

It depends on how bad you think you really want to use that bullet to start with, if it looks like it'll probably shoot, may try two other powders, if it won't shoot on the second one, I might give it one more, or, might say try another bullet to help troubleshoot it. May try 3-4 different bullets in a given gun depending on what I want to do with that gun, may also try up to 3 powders with those bullets. Lots of stuff you just can't tell without trying it out, and then you still need to prove it out, over a decent sized amount of shots, different conditions.