Working up a load. Help me not be nervous.

[BigJ]

Hey guys. I need to work up two different loads for two different guns, and in both cases I will be pushing the limits of the mechanics. I've always gone 'by the book' but I know that (1) the 'book' is conservative (Lyman and Hornady and IMR's website), (2) the guns can take more, and (3) the max load by the book won't get me the velocities I need to get.

To do this safely, my plan is:
1) load 5 shot groups, keeping everything the same except the powder charge
2) start the first group (Group A) at .2 below max as per the book
3) work up the next group (Group B) at max (+0.2 up from the first group)
4) next group (Group C), +0.2 up from the second
5) load up new groups (Groups D thru ... ?) in +0.2 increments until the load is "compressed" (aka I can't hear the powder rattling around in the case when shaking it

Then during range day:
6) Shoot Group A.
7) Study the cases very carefully looking for flat primers, cratered primers, case issues, cracks etc...).
7) If my chrono doesn't have me where I want to be, move on to the next group and shoot it. Look for signs of overpressure etc...
8) Rinse and repeat until I either run out of groups to shoot or my chrono shows my goal.

All ^^that^^ is only my best guess. Please edit/revise/slap me around and set me straight. Like I said, I've never done this before and I'd rather stay on the conservative side here, rather than risk damage or injury.

Thanks in advance.

[h.charlie]

If you have already fired the max per what ever book your using I see no need to start below, but if not proper technique would be starting from minium loads then working up to max, witch should be flattened primers, it is possible to push past this but all certainty fly out the window and should be taken in the smallest babies steps

[eric n]

Why?
Finding pressure is a good thing so you know your danger zone but I've never seen a load that shoots well there, all you are doing is killing your brass. A preconceived speed means nothing if it doesn't shoot well. What type of velocities do you want?
Listen to your gun and not the internet

[BigJ]

Thanks guys.

Why?
Finding pressure is a good thing so you know your danger zone but I've never seen a load that shoots well there, all you are doing is killing your brass. A preconceived speed means nothing if it doesn't shoot well. What type of velocities do you want?
Listen to your gun and not the internet

I hear what you're saying, but I'm trying to keep the bullet supersonic at 1000 yards. This isn't a more-is-better thing; its a can-I-safely-stay-supersonic-at-1k, thing.

[JTROKS]

How long is the barrel? Is it custom or stock?
What caliber?

The guns can take more and seating bullets out decreases pressure and may increase accuracy potential due to minimal jump.

[eric n]

Fair enough...
You wont need 5 rounds to find it. Load up one or two rounds and work up in
.2 increments. When you see pressure signs back off a couple grains and work up with however many you want.... it will save you $ in wasted components.
Be careful and watch the ambient temp.

[BigJ]

How long is the barrel? Is it custom or stock?
What caliber?

The guns can take more and seating bullets out decreases pressure and may increase accuracy potential due to minimal jump.

Service rifle AR15 (20") shooting 80gr SMKs and an M1 shooting 175gr SMKs. Yes, I know, not the right tools for the job, but they're the tools we have so if we want to go learn from the experts on how to shoot 1k, its go with these or don't go at all. Our goal is to learn techniques we can apply at 600yards, not to blow out the X ring at 1k.

Fair enough...
You wont need 5 rounds to find it. Load up one or two rounds and work up in
.2 increments. When you see pressure signs back off a couple grains and work up with however many you want.... it will save you $ in wasted components.
Be careful and watch the ambient temp.

Ok gotcha. So you don't think finding an average is needed? And when you say a "couple of grains" you don't mean full grains by weight, right? Just wanna be sure we're on the same page.

Thanks again.

[drdarrin@sbcglobal.net]

Thanks guys.I hear what you're saying, but I'm trying to keep the bullet supersonic at 1000 yards. This isn't a more-is-better thing; its a can-I-safely-stay-supersonic-at-1k, thing.

Fair enough but accuracy is the other leg of the equation. If you can attain your goal but your groups are measured in feet, have you really gained anything?

[BigJ]

Fair enough but accuracy is the other leg of the equation. If you can attain your goal but your groups are measured in feet, have you really gained anything?

Oh I understand. I'm looking at this as a two step process; given the restrictions of the mechanics of these guns themselves I think the first step is to find the safe upper limit. I'm not convinced that upper limit is still supersonic at 1k. If it isn't, accuracy at any range less than 1k is irrelevant. On the other hand if the upper limit does keep the bullet supersonic at 1k, I will work down from there and see what's the most accurate within the range I have available.

Hope that makes sense.

[JTROKS]

M1A1 in 308 is ok. I hope you have 1/10 twist for those 175 SMK. Update us with your results.

[BigJ]

M1A1 in 308 is ok. I hope you have 1/10 twist for those 175 SMK. Update us with your results.

The standard 3006 M1 barrel is a 4 groove 1 in 10" twist, so no problem there.

Will do on the update.

Open to any other thoughts too. Appreciate it guys.

[readysetgo]

Valar morghulis!

[BigJ]

All men must indeed die!

Lets just hope not this man, this weekend, due to an overloaded and exploding M1!

[Fjold]

In your original post, you talk about working up in 0.2 grain increments from just below the max book value and then increasing the powder charge in 0.2 increments until you get to a compressed load.

Compressing the load is not an indication of anything except that the case is full. It is not an indication of a max load and can have no relation to overpressure. Some powder/load combinations work very well compressed. You can change the amount of compression just by changing your method of loading the powder in the case, i.e. tapping the case to settle the powder, using a long drop tube, etc.



Shooting heavy bullet at or above maximum velocities in an M1 Garand will destroy your rifle. The M1 Garand was designed for light bullets at medium velocities and the operating mechanism cannot take high power loads.

[BigJ]

No offense taken Fjold. This is why I'm asking; rather suffer the scorn of you fine folks than blow up my beloved M1

In your original post, you talk about working up in 0.2 grain increments from just below the max book value and then increasing the powder charge in 0.2 increments until you get to a compressed load.

Compressing the load is not an indication of anything except that the case is full. It is not an indication of a max load and can have no relation to overpressure. Some powder/load combinations work very well compressed. You can change the amount of compression just by changing your method of loading the powder in the case, i.e. tapping the case to settle the powder, using a long drop tube, etc.

Understood. I was thinking that was a place to stop only insofar as I can't really fit much more powder in there, and not so much as an indicator of safe pressures.

Maybe there's a better way to know when enough is enough, before hitting the range?

Shooting heavy bullet at or above maximum velocities in an M1 Garand will destroy your rifle. The M1 Garand was designed for light bullets at medium velocities and the operating mechanism cannot take high power loads.

Agreed totally. And that's why I'm asking. There's lots of data out there saying the 175s can be shot at 2600 or maybe even 2650 fps. What I'm wondering is... how can I creep up on these numbers safely? Or, in other words, maybe a better question is this: will the brass show overpressure signs before the op rod bends? Or no; will the op rod go before overpressure signs are seen in the brass? Or... ?

Same question for the AR. Is the brass the best way to tell enough is enough, or will some mechanical component go before then?

Thanks.