Beginner looking to learn! .300BO load data?

[One Mile Up]

Hello all! First post here on the board...

I've been lurking for a while now, finally decided to try and start getting some info to point me in the right direction... I am looking to get into reloading and am currently looking into the Dillon XL750 so that I can do some volume loading for my 9mm and .300BO.

When working up a load for my .300BO -- I want to make sure I don't blow my face up -OR- get a round stuck in the bore due to a charge that didn't give enough oomph! I am interested in loading supers/subs... however -- after looking around for a while now, I'm having a hard time finding a good "safe" place to start for my specific setup which is:

Sig Sauer MCX Virtus |.300BO | 6.75" barrel | 1:5 twist | Q Thunder Chicken suppressor

My question is: Do I have to worry about the length of the barrel and the twist rate? I have talked to some friends that say "no" I don't -- but when I come in here and look at all the posts from you folks, it _seems_ like I _should_ take this into consideration. Since I am just starting my journey into reloading (TONS of reading!!!) I want to ask people who have a lot of experience and not some buddies who might not actually know the proper way to do things!

My second question is more around case prep....

Should I have a system / machine to do case prep and a machine to reload with? What are the pros / cons of just doing everything on one machine? I'm just trying to figure out what I'm going to buy so that I'm not doing things half-assed.

Thank you for your responses in advance!

Darryl

[20X11]

As far as your second question goes, Since rifle cases often need trimmed for length consistency, most progressive press loaders use a 2 pass process. In the first pass, clean, lube, size/decap, another clean. At this point trim. 2nd pass...primer, powder, powder check, bullet seat, crimp. There are variations on this, and there are trim options for some presses, so these are just general guidelines.

[plant.one]

tiwst rate is a consideration. but only because more twist = more resistance to get down the tube. which *MIGHT* lead to pressure signs earlier than lets say a 8 twist barrel.

so while its something to be conscious of - as long as you're following a good reloading testing regimine and watching for pressure signs, published book minimums will be fine.

that being - setting up a load ladder of min-max charges at 0.5gr intervals and shooting them in that order.

if you dont know how to read pressure signs on your brass - here is a great primer on how to do so
https://www.primalrights.com/library/ar ... g-pressure



one thing to note - dont do you load development with the can on. If you have a stability issue you run the risk of damaging your suppressor due to a baffle or endcap strike. do your testing and chek for stability by looking at the holes in the paper.

if you can find any - heavy cardstock (like 3x5 index card thickness) works great for getting a clean hole without tears.



another thing - especially for someone starting out - BUY A PUBLISHED RELOADING MANUAL to get your data sets from. Hornady's 10th edition has probably the largest published data set for the 300 blk in print to date. $30 well spent IMHO.

[One Mile Up]

GREAT info here gents! Thanks a million for pointing me to the link on how to check for pressure... I am clueless to that (for now). Keep the advice coming!

[cwlongshot]

There are books written in twist rates and how where and when such is better than this and that is superior to that.

Suffice it to say some folks get a lil anal about things.

1:5 is a real fast rate. Most BO are closer to 1:7.

Ya need a fast twist to stabilize long bullets. Ya need faster still to stabilize SLOW LONG bullets.

But ya also CANNOT OVER STABILIZE a bullet. But ya CAN OVER ROTATE one!!

Guns and there barrels are much like people. They have there distinct likes and dis likes. Unfortunately how ya learn this is by shooting and understanding what they tell you thru the reactions the shots give you. It’s a learning curve of where brass falls, shape of bullet holes. Case head expansion, bolt lock up/ speed. Feed and function, case head marks and primer feedback. Kinda mind numbing. Instead of getting lost in there. Shoot the gun. Start with manual loads or factory ammo and have fun and learn.

So before your brain turns to much. Simply said you gonna be fine!

Welcome and ask questions

CW

[dellet]

You always need to match barrel length to what you are shooting and what you expect to accomplish. A short barrel brings a few things to consider, a fast twist a couple more.

The short barrel and supers or fast powders can be very hard on suppressors. Q is one of the few manufacturers that does not limit a minimum barrel length. There will be a few people that will take advantage of that warranted. A mag dump or two, running full auto with supers will have that can glowing red. Repeatedly this will take it's toll.

The fast twist rate will have no measurable effect on pressure. It can tho cause problems with bullets.

Speed does not really damage bullets, RPM, spin will destroy bullets. Particularly those with thin jackets and many expanding bullets will come apart in flight. The hotter the barrel gets, the more this can become a problem. Staying under 2000 fps is a good idea.

Over spun bullets are harder to gain the maximum accuracy potential, but MOA is reasonably easy to achieve.Dimes at 100 yards are not a problem.

Do not be lulled into thinking subs are safe from pressure issues because they are low velocity. Many of my sub loads operate at a higher pressure than my supers.

In general it's no different than a 1/10 twist, with the exception that the bullets are under twice the rotational stress.

[One Mile Up]

Interesting...

So, is there a tool (online preferably) where I can simply put in my barrel caliber, length, twist and get some good starting points for safe load data regarding supersonic / subsonic loads?

p.s. I'm loving the great info here!

[dellet]

Load data is load data. Published data should be considered safe, you will just have lower velocity. With certain powders with subs you might get to the higher end of pressures. Just stick with the data.

JBM has multiple calculators, including stability. Not something you need to worry about too much with a 1/5, but it's good to check for some long bullets.

For spin rates, your on your own. Very few manufacturers publish or will even tell you the high end, but it's worth a call or email. Most are safe to 250,000 rpm. Some as high as 350,000, some as low as 200,000. The formula for spin rate is 12/twist X 60 X velocity.

12/5 X 60 X 2000 = 288,000.

The hotter the barrel and bullet, the lower the RPM the bullet will come apart at.

[One Mile Up]

Load data is load data. Published data should be considered safe, you will just have lower velocity. With certain powders with subs you might get to the higher end of pressures. Just stick with the data.

Thank you fine, sir -- I _do_ appreciate the input!

[cpnbnanamn]

tiwst rate is a consideration. but only because more twist = more resistance to get down the tube. which *MIGHT* lead to pressure signs earlier than lets say a 8 twist barrel.

so while its something to be conscious of - as long as you're following a good reloading testing regimine and watching for pressure signs, published book minimums will be fine.

that being - setting up a load ladder of min-max charges at 0.5gr intervals and shooting them in that order.

if you dont know how to read pressure signs on your brass - here is a great primer on how to do so
https://www.primalrights.com/library/ar ... g-pressure



one thing to note - dont do you load development with the can on. If you have a stability issue you run the risk of damaging your suppressor due to a baffle or endcap strike. do your testing and chek for stability by looking at the holes in the paper.

if you can find any - heavy cardstock (like 3x5 index card thickness) works great for getting a clean hole without tears.



another thing - especially for someone starting out - BUY A PUBLISHED RELOADING MANUAL to get your data sets from. Hornady's 10th edition has probably the largest published data set for the 300 blk in print to date. $30 well spent IMHO.

Wow.. Sorry to resurrect a slightly older thread, but this is GREAT info for a newbie to 300blk. I'm doing a ton of reading as well, but these are some points that sum up what I need to know, as well as many others made in this thread.
I'm going to be reloading for a BPM AR pistol, 7.5", 1:8, and am planning on using a can.. Mostly I'm wanting this got defense and plinking.

So here's my question.. For use with a can, I want to stay in the subsonic range, correct? That's the impression I'm getting. The BAD news is, I'm playing hell finding projectiles. I've got a lot of 5.56 once-fired brass that I'm going to be resizing, but need all the components to make this work.

As for Reloading data, I've got an older Hornady (3rd ed.) book, but 300BLK isn't in that, or in my old Lyman book. Guess I need to get an newer one!