"c" after load? No 168g bullet in data? Load over max gr?

[christopher0452]

I am new to reloading (picked a great time with all the AVAILABLE components out there!) and find it intoxicating. However, I do have a few questions, perhaps a bit simplistic, but I'd like to ask the "gurus."
1. I know the small "c" after a grain amount eg; 65.0c, means compressed. What DOES that mean to me as a reloader.
2. I have noticed in many load data charts that they jump from 165/155 etc. directly to 180g. Now, I have been loading 168g HPBT in my 300WSM. Since they do not have the grain listed (168g), is it permissible to use a lower or higher grain bullet data, or just extrapolate between the choices?
3. Sometimes, I'll have a certain powder, but it is used for the 180g bullet, while another powder is used for the 168g (powder I do not have). Again, is it ok to use these numbers even though they apply to a larger bullet?
4. Finally, I have been told "official" load data sheets are conservative.....no lawyer speak now....can one exceed the max number, carefully and in small amounts, while paying attention to pressure issues?

Thank you for your assistance

 

[MSU Marksman]

1. If you take a case and rattle it next to your ear, you'll hear the powder shaking around. If you don't hear it shaking around, that's because it's "compressed" or packed tightly when the bullet is seated.
2. As far as the difference between 165gr and 168gr, assuming you're talking about 30 caliber bullets, they are close enough that you can use the same data between the two.
3. I'm not exactly sure what your question is, so I'm not going to comment.
4. Yes and no. The numbers listed are a little dialed back from maximum pressure, but that is because the data books don't know the age or quality of your rifle. To be safe, they assume worst case scenario. That said, I have some modern and custom rifles that are built to better tolerances which I regularly load over maximum listed data. As long as you're watching for pressure signs as you go, you should be fine.

 

[Wile E Coyote]

3. Sometimes, I'll have a certain powder, but it is used for the 180g bullet, while another powder is used for the 168g (powder I do not have). Again, is it ok to use these numbers even though they apply to a larger bullet?

The short answer is "NO".

Yourself being new to reloading, if it isn't expressly published in one of the manuals, don't do it for safety's sake. Even when it is published, the MAX load is not the starting point. Begin in the middle and work up. Bad things could happen if you don't.

I'll qualify that last sentence by saying I was once party to the destruction of a perfectly good sporterized 03 Springfield because we didn't pay attention to the recommended book loads.

Pete

 

[ShootnMathews]

3. Sometimes, I'll have a certain powder, but it is used for the 180g bullet, while another powder is used for the 168g (powder I do not have). Again, is it ok to use these numbers even though they apply to a larger bullet?

Are you asking if you can use the powder recommended for the 180 grain bullets with the 168 grain bullet??

 

[varmintH8R]

I'll put my 2C in on #3 and #4

#3. If I can't find data for the powder I want to use for a specific bullet weight, I won't use it. I agree with 165 gr vs 168 gr, or even backing off if the data is 160 vs 168. More than that, I'm not experimenting. Usually you can always find data for the powder you want if you check enough places. Powder manufacturers and many bullet manufacturers put data online, it's a good back up to your manuals. Also note that bullets of the same weight with different profiles will create different pressures under the same charge. Always work up conservatively when switching bullets.

#4. I feel pretty strongly about this one. I personally do not exceed the highest published max load for any round I load, and ill only go to max after an extensive work-up. I prefer if I can find an accuracy node a little bit under max. To me it is a question of risk vs reward - is there any tangible benefit to pushing the envelope with any given load? Does another 50fps really do anything for me? Is that 50fps worth a potential BOOM? To me, it's not even a question. If you are a highly experienced wildcatter and really know what you are doing, more power to you and this post isnt meant to judge. If you're not, I would set max slightly below max (assuming of course you work up safely to this point)

My opinion only.

 

[Lefty7mmstw]

There's plenty of time for rubber underwear while wildcatting and playing with mil surp powders and those powders without data for your chambering after you get your feet wet. Take your time and ask questions, even if they seem small or unimportant.

+1 on varmintH8R's comments

One thing I'll add is to not chase performance above safety; there's nearly always a larger chambering that will get you the desired performance safely. Load shopping ( going to the highest charges you can find) and trying for new frontiers ( ie. over book loads) are two of the primary reasons that rifle makers usually won't warrant a rifle damaged by reloaded ammo.

Don't get yourself in the running for a Darwin award.

I realize talk about safety can be a buzz kill, but most of the guys here ( me included) have run into at least one situation that could had been avoided by showing the proper respect for the game at hand.

 

[g0rd0]

a 170 grn rn (7mm rem mag) is 66 grn IMR 7828 max
a 175 grn sp (7mm rem mag) is 61 grn IMR 7828 max,
so, if you where to use the 61 grn in your 170 grn load ok, but, if you where to put 66 grn in your 175 grn you would have a very good chance of destroying your rifle and maybe a trip to the er.
In a short answer stay with published load data and conferm your data with a different puplisher (Hogden web site X with a manual or the Alliant web site X with a manual) I use the Lee manual and x with Alliant and Hogden site, my way of doing it.
And yes the books are listed low in my opinion but, stick with it. Unless of course you are a thrill seeker.

 

[Lefty7mmstw]

I've got a couple of rifles I can't go to most max loads with without getting high pressure signs. Some of my rifles eat max loads with impunity and ask for more. Get your feet wet before playing games with the system.

Most of the time if two similar weight bullets show off the wall changes in powder charge it is either different bullet construction or bearing surface. Basically the bullets are acting like they are much different weights than they are resistance wise in the bore. That's the biggest reason most bullet makers specify that the data is for their bullets only.

 

[SidecarFlip]

There's plenty of time for rubber underwear while wildcatting and playing with mil surp powders and those powders without data for your chambering after you get your feet wet. Take your time and ask questions, even if they seem small or unimportant.

+1 on varmintH8R's comments

One thing I'll add is to not chase performance above safety; there's nearly always a larger chambering that will get you the desired performance safely. Load shopping ( going to the highest charges you can find) and trying for new frontiers ( ie. over book loads) are two of the primary reasons that rifle makers usually won't warrant a rifle damaged by reloaded ammo.

Don't get yourself in the running for a Darwin award.

I realize talk about safety can be a buzz kill, but most of the guys here ( me included) have run into at least one situation that could had been avoided by showing the proper respect for the game at hand.

The rubber underwear are for, when you drop a turd from scaring yourself shitless, it's easier to clean up after. Stick to book powders, loads and avoid maximum loads. Off data powder can be used if, if you can sumrmise the comparable burn rate. If not, don't play. Fingers, eyes and life are more important than playing with the unknown.

 

[RockyMtnMT]

The rubber underwear are for, when you drop a turd from scaring yourself shitless, it's easier to clean up after. Stick to book powders, loads and avoid maximum loads. Off data powder can be used if, if you can sumrmise the comparable burn rate. If not, don't play. Fingers, eyes and life are more important than playing with the unknown.

Burn rates can be misleading as well. A call to the powder manufacture or the bullet manufacture for what you want to use will usually get you a start point to work up from. You should shoot over a chronograph. The max velocity is really the max load. Some rifles will take more powder to reach max velocity some take less. I takes the max pressure to achieve the max velocity. Velocities that are way over load data should be considered risky.

Have fun. Rolling your own is very satisfying.

Steve

ps

Rubber underwear would be helpful sometimes. I'll remember that with the next un known recipe that I start.

 

[SidecarFlip]

An American pastime, getting the most from anything, velocity included. However, maximum velocity don't always equate to maximum accuracy, actually, most times it don't. I don't believe I load anything at maximum velocity. Usually accuracy comes somewhere lower depending on caliber family, sometimes much lower.

I get a kick out of the Hornady ad with the cartridge looking like a dragster engine. Cute but in reality, not accurate.

 

[christopher0452]

Thanks to you folks that took some time to address my questions. All valuable information I will consider and incorporate into my reloading exploration!