Reloading for 308 Garand with 8208 XBR

[*chris*]

I need to develop a load for my 308 chambered Garand and have some 150gn bullets and 8208 XBR.

I have read that modern factory ammo is "too hot" but have not been able to find any stats as to what that tangibly means.

Obviously I need enough powder to cycle the action but when do I know I have enough and/or too much powder?

Chris

 

[mac1911]

I don't know for sure if a 308 chambered garand faces the same challenges of a 30-06 chambered garand. The short rule of thumb is stay with in powders with burn rates of IMR 4895.

It's not about the cycling of the action. It's the port preasure that affect the Operating rod.
To much preasure or volume and the op rod gets slammed and possibly bent.

 

[jasons]

8208 has some weird peak pressure characteristics. I'm not sure I'd use it in a Garand at all, but if I had to I personally wouldn't push much past the minimum load.

 

[*chris*]

the op rod gets slammed and possibly bent.

How do you know when it is getting "slammed?"

Chris

 

[mac1911]

The range of "safe" burn rates are between IMR 3031 and IMR 4064. I failed with 3031 and 4064 in my garands for a accurate load. I found Varget and H or IMR 4895 to deliver. I have since stuck with target.
There was some talk on cmp forums when 8208 first came out and as Jason's mentioned several people posted concerns of the pressures developed to get XXxX velocity vs other powders.

 

[mac1911]

How do you know when it is getting "slammed?"

Chris

Good question....., I,have only witnessed one bent op rod with a shooter who was shooting federal power shok 180 grain ammunition. Claims he had put over 500 rounds through it with out issue until the op rod came off and was visually bent, made it to the sitting rapid stage that day. I think the issue is when you go out of the safety net of the known safe powders the affects tend to be cumulative and slowly wear on the rifle until it's to late...you will be hard pressed to damage the receiver with any powder safe for 30-06 in the M1.
As for 308 it may have its own quirks in the M1.

You could email IMR and see if they will give you data for M1 308 loads

 

[jasons]

There was some talk on cmp forums when 8208 first came out and as Jason's mentioned several people posted concerns of the pressures developed to get XXxX velocity vs other powders.

Yeah, apparently the pressure peak is early in the burn and fairly high in amplitude but relatively short in duration compared to other powders used for similar loads. To get decent performance out of it you either have the live with the higher than normal initial pressure spike (assuming your gun can take it) or settle for lower velocities (and hope it will cycle.)

That, and the difference between a safe accurate load that will cycle reliably and an over-pressure load is slim. I'm not saying it's a bad powder - on the contrary I know a few guys who swear by it, just that it deserves a little extra care when working up loads. Especially in a rifle that's known to be sensitive to high pressure loads.

 

[jpm]

How do you know when it is getting "slammed?"

Chris

you can actually hear it, at least I can. You get used to the sound of the action cycling when you shoot garand appropriate ammo, when you shoot something that slams the op rod, you can actually hear it hitting harder and louder. I had this with some 168gr handloads I made that were seated a bit too deep. I backed the next batch out a good bit with the same charge and it sounded and cycled normal again. It really sounded harsh with the higher pressure stuff.

 

[*chris*]

Ok, I think I will head out to Harvard tomorrow morning to test out some 2500 FPS loads which is a bit below the published maximum.

I sold all my Varget but I do have some 748, is this a good powder as well?

Chris

 

[jasons]

Ok, I think I will head out to Harvard tomorrow morning to test out some 2500 FPS loads which is a bit below the published maximum.

I sold all my Varget but I do have some 748, is this a good powder as well?

Chris

I use 748 for 55 grain .223 plinking loads. I've never tried it with anything bigger.

 

[*chris*]

I use 748 for 55 grain .223 plinking loads. I've never tried it with anything bigger.

There is data for it in the Hornady manual. I am not a big rifle shooter, so I don't have many different rifle powders. I use Varget/748/8208XBR in my .223 loads.

The 8208XBR seems closest in burn rate to IMR4895 should it should work. I need to watch for pressure as you say.

Thanks for the advice!

Chris

- - - Updated - - -

You could email IMR and see if they will give you data for M1 308 loads

Good call, I will call them on Monday. They helped me build loads for the S&W 500 and titegroup.

Chris

 

[jasons]

There is data for it in the Hornady manual. I am not a big rifle shooter, so I don't have many different rifle powders. I use Varget/748/8208XBR in my .223 loads.

Out of those three I'd try Varget first.

 

[DW357]

I've had good results with IMR-4064 in 30-06 for my Garand. Need to make more. I tried Varget and H4895 but with the limited rounds I made (~30 with each powder), 4064 seemed to shoot the best. But I need to do more testing. I don't know how well it works in 308 though.

 

[mac1911]

Although the gas systems are different hornady 7th manual has a section for 308 service rifle m1a/m14
The powder range is similar to garands?

 

[*chris*]

I loaded some Lake City 2011 brass with Hornady jacketed 150 grain projectiles and 41.5 grains of 8208 XBR. The hornady manual states this should produce 2500 FPS out of a 22" 1 in 12" twist barrel. I think the Garand has a 24" 1 in 10 twist barrel. I did not weigh individual components, but the finished rounds were within 3 grains of each other. I weighed each charge so the variance was with the brass and projectiles. My results out of the shooting chrony for 10 shots:

low - 2645
high - 2777
avg - 2715
ES - 132
SD - 39

I am not sure if there is something wrong with my chrony or it isn't that accurate but I always get similar SDs out of it even with factory ammo. This is a brand new barrel and was shots 30-40 through the barrel that day.

The velocities are quite a bit higher than the manual, but still seem reasonable. The rounds seemed accurate. The brass was ejecting around 4-5 oclock and the rifle "sounded" fine and nothing was bent when I got home. Am I done? What velocities are others using for the target ammo?

Chris

 

[mac1911]

If its any help ( Im referring to 30_06 M1) when I started reloading I was trying to duplicate M2 ball velocity of 2700fps. Well let's just say thats over kill and my accuracy was not great.
Out of my 4 rifles I have taken the time to test 150gn Hornady & Varget running a average of 2542fps delivers some of my best groups. I never bothered to run these over the crony but my A max and nosler CC do well at a even slightly less charge.

My most accurate load in,my best rifle is 168 nosler CC with varget running just above hornady manual minimum charge. They run just under 2moa. The velocity on those by memory was around 2400fps. Been a while. As I upped the charge groups opened up.

For 308 your max loads are probably less or close to 30-06 garland starting loads.

I only shoot out to 200 yards for score so I want accuracy vs velocity.
The garand can cycle on pretty low charges. I experimented with cast bullets out of my garand with H4895 and got it to cycle fine at some H4895 reduced load charges suitable for cast bullets.

 

[*chris*]

If its any help ( Im referring to 30_06 M1) when I started reloading I was trying to duplicate M2 ball velocity of 2700fps. Well let's just say thats over kill and my accuracy was not great.
Out of my 4 rifles I have taken the time to test 150gn Hornady & Varget running a average of 2542fps delivers some of my best groups. I never bothered to run these over the crony but my A max and nosler CC do well at a even slightly less charge.

My most accurate load in,my best rifle is 168 nosler CC with varget running just above hornady manual minimum charge. They run just under 2moa. The velocity on those by memory was around 2400fps. Been a while. As I upped the charge groups opened up.

For 308 your max loads are probably less or close to 30-06 garland starting loads.

I only shoot out to 200 yards for score so I want accuracy vs velocity.
The garand can cycle on pretty low charges. I experimented with cast bullets out of my garand with H4895 and got it to cycle fine at some H4895 reduced load charges suitable for cast bullets.

Good to hear this, I was aiming for a 2500 FPS load. I am looking for accuracy as well potentially out to 300 yards, but I don't trust myself with iron sights that far yet. I am in the middle of the Hornady manual right now at 41.5gn of 8208 XBR. They suggest from 39 gn to 44.2 gn resulting in 2300 FPS to 2700 FPS. I will drop down to 40.5 gn and see if that drops me down to 2500 FPS.

You make another interesting point that the max pressure of the 30-06 round higher than the 308 round. That means even a powerful 308 round will have less impact on the gun than a moderate 30-06 round. I don't reload 30-06 so I don't know much about it.

Chris

 

[mac1911]

Good to hear this, I was aiming for a 2500 FPS load. I am looking for accuracy as well potentially out to 300 yards, but I don't trust myself with iron sights that far yet. I am in the middle of the Hornady manual right now at 41.5gn of 8208 XBR. They suggest from 39 gn to 44.2 gn resulting in 2300 FPS to 2700 FPS. I will drop down to 40.5 gn and see if that drops me down to 2500 FPS.

You make another interesting point that the max pressure of the 30-06 round higher than the 308 round. That means even a powerful 308 round will have less impact on the gun than a moderate 30-06 round. I don't reload 30-06 so I don't know much about it.

Chris

You can get into trouble with chamber preasures with either one ..... stay within published data and your CHAMBER will take it... OP rod or gas system is a different story. As I stated you may not see or feel or here any damage being done. I personally because of my frugal side would start with the lowest published minimum charge with any of the published powders. If it functions and groups well thats what I look for.

 

[*chris*]

I personally because of my frugal side would start with the lowest published minimum charge with any of the published powders.

That is how I used to test new powders, but have run into cycling issues too many times to count. Now I start somewhere in the middle of the range and see how it works. The powder costs 14.7 cents per round so going up our down less than 10% isn't too significant.

Chris

 

[mac1911]

That is how I used to test new powders, but have run into cycling issues too many times to count. Now I start somewhere in the middle of the range and see how it works. The powder costs 14.7 cents per round so going up our down less than 10% isn't too significant.

Chris

true, but when your frugal its not the actual amount !