Thread: Factory loads exceeding reload speeds with less pressure signs

Hi,

I am reloading for my 16inch 308, currently playing with ar2208, 43g 150gsst. This round is extremely accurate but giving me speeds of around 2400fps and showing pressure signs (flattened primers). I grabbed a factory Sako round, 150g and that’s pushing 2650fps with absolutely no pressure signs at all.

What is Sako doing differently to get so much more speed out of the round? I have to go back down to about 2340fps so the primers are not getting pancaked. Cheers

You could try Leverevolution powder, it tends to give very good results in shorter barrels, I currently use it in a 16.5" 223 and the results were nothing short of amazing - same in a 6 ARC I ran for a while. It is a similar speed to AR2208/Varget (that DOES NOT mean loads are interchangeable) and there is load data out there for it in the 308.

Brass?
How much are you bumping the shoulder on the handloads?

could be lots of things and I'm not the expert here.
However I see Hodgdon list a 150gr max with 2208 of 2900fps with a 24" barrel while I see some other powders get up to 3000 fps.
The Sako loads are listed at 2850 and you are getting 2650 with them so thats about right with a 25 fps velocity loss per inch of barrel.

Could be a number if things, have you checked your COA (Overal lengths), neck tension, and harder to deal iwth is case volume. You may be using brass with a small powder volume, (thicker brass and base). This will push up pressure and at the same time limit velocity due to a lack of power (energy).

Can you list the brass, primers and charge weight you are using. Then someone with more experiance than me may be aboe to chime in.
Z

It is most likely the combination of the components used is able to generate higher velocity with less peak pressure.

I'm lead to believe that ammo manufacturers can often have access to powders or a blend of powders we don't.

I’m using Norma brass, Winchester primers and the COL is 2.810 43.3G charge weight. If I increase the COL will that increase case volume and thus help with pressure?

Greetings @Stephanhope,
Primer appearance is practically worthless for guessing pressure. @gimp is onto it asking about your shoulder bump as too much headspace will show flat primers at low pressure. 43 grains of AR2208 with the 150 grain in the .308 is piss weak and below start loads. 47 grains is book max which would give you roughly an additional 200 fps or you guessed it 2,600 fps. The problem is that you being misled by the primer. You are clearly sizing your cases too much and setting the shoulder back. This will give you head separations in time. There is nothing wrong with the powder you just aren't using enough.
Regards Grandpamac.

Im relatively new to reloading, but I’m running my brass through a FL resizing die, should I be doing something different? Cheers

Greetings again @Stefanhope,
First order of business is to stop oversizing the cases. I use the Redding competition shell holders but they are expensive and you may only use one. See if you can find someone local who has a set. You can set up the die off the shell holder by trial and error but it is not as accurate and very frustrating. COL makes bugger all difference to pressure at near normal settings. There are several .308 rifles here and they all need +0.004" shell holder or more other than the target rifles.
GPM.

Originally Posted by Stefanhope

Im relatively new to reloading, but I’m running my brass through a FL resizing die, should I be doing something different? Cheers

Back your die out 2 full turns then size a case and see if it chambers in the rifle. Screw the die in 1/8th of a turn and repeat the process until the brass chambers with a little resistance on the bolt

Forget about your primers. Some are soft. Some are hard. The chronograph is telling you what is going on; very low pressure. Put 47 grains in and go and shoot it. I am sure you will be pleased.

(And do what Trav above says with your f/l sizing die. It's not really hurting you, but your brass will last longer.)

Originally Posted by Stefanhope

Im relatively new to reloading, but I’m running my brass through a FL resizing die, should I be doing something different? Cheers

It is just a matter of setting the FL die up so it is not oversizing the case which is the cause of the flat primers. I used to neck size but this can cause it's own set of problems and I have dumped it other than for light loads. I did try using a feeler gauge to set the die slightly off the shell holder working up the gauges until a sized case just chambers tight and then backing off a couple of thou but it is extra fiddly. The other option is to just ignore the primers and check the cases each load with a bent paper clip to see if they are developing a groove inside the case just above the head. It would greatly help if you could find a local mentor to help you through the initial stages of learning handloading. There is an awful lot to learn and a lot of myth. Will post again tomorrow.
GPM.

Grandpamac basically suggested what I was going to say - light load with a case resized past what's needed can create this issue. What happens is the firing pin slaps the case forward and the pressure generated by the powder doesn't shove the case back. Something has to give, and in this case it's likely the primer shifting backwards.

As noted - the load is quite light per the current recommendations as well although in the past the loads have been lower so it's not in itself a safety concern and I would think that there are a number of issues that are contributing.

As far as setting up the full length die - I would suggest firstly checking a factory load case fired in that rifle and making sure it chambers again. Then mark the neck and shoulder up with vivid marker pen and wait for it to dry, after the cleaning and brush the neck out and a bit of lube inside obviously. Set up your shellholder in the press, move it all the way up without the case in and with the ram fully up wind the die down until it contacts the shellholder. Then back it off one turn, and lock it into place. Retract the ram, chuck the marked case in and send it up and see where the marker pen has been scraped off the neck. That will tell you how far down the case the die is going, you basically want it just short of the shoulder and if you get stiff closing of the bolt on reloaded rounds just adjust the die a little further down. Somewhere on here is a picture showing how many thous approximately is 1/8 turn on a standard die, I think it was 10 thou (0.1mm is about 40thou for our purposes thats close enough anyway).

Greetings @Stefanhope,
I am always reluctant to suggest new kit to new handloaders like yourself but you could consider the Hornady headspace comparator kit. This allows you to measure the amount that you are setting back the shoulder when full length sizing and greatly simplifies adjusting the die to get the desirable 0.002" (0.05mm) set back. The device clamps onto the jaws of your calliper and comes with a set of barrels for different case dia. Have a look at the Hornady vid.
Looking at my notes I chronographed the start load of 44 grains of AR2208 in a 20" barrel with the 150 grain at 2,560 fps and 45 grains and 25 grains in a 24" barrel for 2,760 fps. Your results line up with these once differences in charge and barrel length are allowed for. I would consider increasing your charge to 45 grains of AR2208 which is still only a mid load and should chronograph around 2,500 fps.
All the best and regards Grandpamac.

[QUOTE= I think it was 10 thou (0.1mm is about 40thou for our purposes thats close enough anyway).[/QUOTE]


I don't mean to be picky but 0.1mm is boat load closer to 4 thou than 40. Lets not make it harder for the bloke than it already is