Min 308 load data with 7.62 x 51 brass.

[Patriot Shooter]

First I would like to say thanks to all of you for helping to educate me in reloading. I am just getting into reloading and doing lots of homework before getting started. Reading your posts has helped alot, and given me more subject matter to study too.
I do have a question I hope you can help me with dealing with 308 min load data when loading for 7.62 x 51 brass. I know I have to use 308 load data and reduce the powder a little. I am also going to be using CCI #34 primers, which I understand act like magnum primers, and I must reduce the load again. So, just how much can I reduce the load below given 308 data and still be safe. The bullet will be 155gr SMK's and powder, I am undecided as of yet. Since I want to go by the book and work my way up to develope a load, I am kinda confussed at where to start, since it seems using these components will put me closer to max at the beginning and leave little room before seeing pressure signs.
As far as using the #34 primers, I am loading for a Semi Auto, and figured untill I get good at seating primers properly, this would be a good way to go. I know there are different opinions about using them, but I already have 2000 of them now.
Thanks for any help in getting me started.

 

[USSR]

If you are talking about starting load data in reloading manuals using .308 Win brass, then you are okay using that in 7.62x51 brass. Other than that, I find that a 1.5gr reduction in charge weight is a good place to be with 7.62x51 brass. Traditional powders to use are IMR4895, H4895, and IMR4064. Hope that helps.

Don

 

[ldlfh7]

I shoot lc brass out of my bolt rifle and love it. I take it down 1.5 gr from the max but not the min. I start out at 308 win load suggestions and work it up to the max charge -1.5 grains. Never shown any signs of high pressure or cracked cases. The difference between 308 win and 7.62 NATO is negligible. My biggest problem was resizing the NATO brass shoulder back far enough to chamber in my rifle. All I did was screw my resizing die in a tad more and then I was good to go.

 

[Patriot Shooter]

Thanks for the info, I think I will try H4895 and start 1.5 grains below min and work my way up, not going over the max -1.5 grains. I guess doing some water volume measurements on my LC brass will be a good idea too, just to see how much difference there is between it and 308 brass. This should safely get me some expeirence at reloading high pressure rifle ammo.
Thanks again for your input.

 

[rcmodel]

and start 1.5 grains below min

NOOOO!

Use the starting load and do not reduce it any further.

Using military brass is not rocket science.

There is no practical difference in starting loads when using military brass, or military spec primers..
That's why they are called starting loads.

They are safe in any brass & with any primers you might have on hand.

The difference is when you get up near the MAX loads.

Then you need to wake up and start paying attention to what's going on.

rc

 

[oldpapps]

Heed what RC stated.

You may look for minimal 'starting loads' in the pistol section of Hodgon's web site. As you are feeding a self loader, there is the possibility that they may be too light. Try them, the 'LISTED STARTING LOAD'.

Some powders become very erratic. Things like 'detonation' and poor ignition due to the propellent being spread out loosely in a cavernous cartridge.

For your safety, follow what RC says, please.

 

[driftpin]

Again start at min and work up, and I see a lot of beginning reloaders pressing towards that MAX compressed powder charge to achieve the max velocity (or so they think it will) but I find with most, not all but most cartridges shoot best when they are 150-200fps below their max. Pushing the max all the time too will cost you money from your equipment getting beat up, you'll burn out your barrels quicker and you won't get that many loads out of your brass and your plainly wasting powder thats firing out and not being burnt. The number 34 primers aren't your problem. I use them in all my semi autos unless I'm shooting one at a time. Separate your mil brass from your regular and don't mix them up. Stay right in the middle or just a touch higher but there is no need when working up loads to max out. IMHO.

 

[Slamfire]

I have shot the 155’s with IMR 4895 and 42.5 grains is a fine load. If you plan to use your 155 grain load in a gas gun, such as AR10 or M1a, this load is appropriate for the gas system.

[SIZE="3"][B]Ruger M77 MKII 	[/B]		
26 " Barrel 1:10 twist					
					
155 Nosler Match 42.5 grs IMR 4895  wtd lot L7926 mfgr 2000 TZZ  Brass CC#34  
	 	OAL 2.750" 			
4 July 2009  T =  86 °F					
						
Ave Vel =	2716					
Std Dev =	33					
ES =	113					
High =	2794					
Low =	2681					
N =	10					
					
[B]Pre-64 M70 [/B]					
24 " Krieger  Barrel 	1:10 twist				
							
							
155 Nosler 42.0 grs IMR 4895  thrown, Lot L7926 TZ cases CCI#34  OAL 2.750"	
							
29 May 2010 T =  83 °F						
							
Ave Vel =	2677				 		
Std Dev =	27				 		
ES =	76				 		
High =	2727				 		
Low =	2651				 		
N =	8[/SIZE]

 

[Patriot Shooter]

Ok, I think I understand now, don't change the starting load, and stay 1.5 grains under the max. I was thinking going below the starting load was the wrong thing to do after I posted my reply. Thanks for keeping me straight on that fellows
Thanks for the load info Slamfire1. That sounds like a good load for me. Not as a starting point, but to use as a guide of course. However it looks like there is some difference in the Nosler's and the SMK's.
IMR's website lists starting load of 43.5 for the 155 SMK's and the Nosler #7 book lists 40.5 for the 155 Nosler CC's, both using IMR 4895. Is there really that much difference in the two bullets? And will I get less recoil if I use the Nosler's? That would be a plus.
Since I don't have the bullets yet, I will use the min load given for which ever one I get, and work up from there. However this does make me see that if I don't have the load data for a certain bullet, don't just pick one that is similar and go from there. Am I right in this observation?
Thanks again everyone, your help is appreciated

 

[USSR]

However it looks like there is some difference in the Nosler's and the SMK's.
IMR's website lists starting load of 43.5 for the 155 SMK's and the Nosler #7 book lists 40.5 for the 155 Nosler CC's, both using IMR 4895. Is there really that much difference in the two bullets?

No, there is essentially no difference between the 2 bullets as far as load data goes. Load data will vary in different load manuals. The primary difference in this case is that the IMR load data was obtained using Winchester brass, which has the most case capacity. In this case, use the Nosler #7 starting load data.

Don

 

[driftpin]

They may be the same weight and have similar profiles but when pulling a load out of say the Hornady Manual, pay attention to what they say that the OAL was used when testing that specific bullet, especially when you are close to the max. I personally like H-4895 for my autos, it dispenses better for me. Just take a load you like and start in the middle. If a load says min. 39.5 gr of Varget, Max being 43.5, start at like 40.5 or 41 and work up until your satisfied or see signs of high pressure. If you are unsure of where the bullet's manufactured then start at 2.800" if your gun allows you to play with OALs you can adjust there to fine tune. Some rifles like the bullets right up close to the lands and others don't mind the jump. Just be caution, I'd rather stay just a bit higher than the middle of the road load unless I'm hunting, it's easier on your equipment, shoulder and brass.

If you have a M1A than you need to do a lot of research before reloading for them. I was only comfortable using the 2- 4895s and 4064, 3031 with the M1As gas system being so temperamental. Good luck and enjoy.

 

[ArchAngelCD]

Do all the military 7.62X51 brass brands have a smaller capacity than the commercial stuff? I know not all the 223 brass has a smaller capacity, only some do.

 

[USSR]

ArchAngelCD,

I can't say "all", as I have only used LC, RA, and a German M80 brass whose headstamp name escapes me at this time. Like all the Winchester brass, they appear to be the lightest with the most case capacity. Lapua brass is quite heavy, and falls between most commercial brass and the military brass.

Don

P.S. - What the heck you doing up at 3 am?

 

[W.E.G.]

If you want a powder-puff .308 or 30-06 load, you can reduce your "normal" load by 5 full grains, and end up with a load that is accurate enough, and which you can shoot all day.

This may end up being less than the "starting" load listed in the manuals. It will still shoot fine at 200 yards.

Best accuracy is usually somewhere close to the max load.
Acceptable accuracy can be had at much lesser recoil.

I shoot 38 grains IMR 4895 with a 135-grain bullet in the 1903 Springfield.
Its a joy to shoot.

 

[kerreckt]

Right or wrong I never start with the minimum. I always start with slightly less than the mid amount. This is true regardless of caliber or brass. I have observed that my best accuracy is almost always close to the max. This is a big generalization but also a truth in my experience. I am reloading for firearms in excellent condition the oldest being a Springfield '03 made in 1918.

 

[ArchAngelCD]

ArchAngelCD,

P.S. - What the heck you doing up at 3 am?

Take a look at all my posts. They are mostly between midnight and 5 AM. (except for today) I can't sleep at night so I sit up posting on this and a few other shooting related forums! If fairly sure I have insomnia...

 

[Patriot Shooter]

Thanks for all the info!

I am up at all hours too ArchAngelCD. Shift worker and insomniact.

I am loading for a DPMS 308LR with 16in barrel, and am wanting a little less recoil than M80 ammo, and of course more consistant accuracy. Thanks again for all the info. Oh, and my brass is LC.

I cant wait to start reloading, but still lots to learn. LOL

 

[Robert101]

Op, you didn't state the powder you intend to use. I typically use H4895 or Varget in the 308 Winchester and sometimes I do load below minimum book stated levels in my semi-automatics. For instance, in my DPMS TAC20 I've used as little as 33 grains of H4895 for about 2,200 fps. This keeps the operating pressure around 33,000 psi and does function fine in my rifle without problem. I do not suggest this as a starting load but was intended as an experiment in my weapon. H4895 is also not knownn to cause problems at reduced charge weights in the 308 case. If I start loading with a new powder I do initially stay within the parameters established by the BOOKS.

 

[ArchAngelCD]

Op, you didn't state the powder you intend to use. I typically use H4895 or Varget in the 308 Winchester and sometimes I do load below minimum book stated levels in my semi-automatics. For instance, in my DPMS TAC20 I've used as little as 33 grains of H4895 for about 2,200 fps. This keeps the operating pressure around 33,000 psi and does function fine in my rifle without problem. I do not suggest this as a starting load but was intended as an experiment in my weapon. H4895 is also not knownn to cause problems at reduced charge weights in the 308 case. If I start loading with a new powder I do initially stay within the parameters established by the BOOKS.

H4895 was specifically tested at reduced pressures and it's the powder Hodgdon recommends for reduced rifle loads for many cartridges. http://hodgdon.com/PDF/H4895 Reduced Rifle Loads.pdf

The powders I like best for loading the .308 depending on the circumstances are Varget, BL-C(2) and IMR4064. Of course there's nothing wrong with H4895, IMR4895, AA2520 and AA2495 either.

 

[driftpin]

I couldn't have given better advice, excellent ways to explain it. I just tend to be toward the right of the middle (the right being a higher amount of case capacity/pressures.)