So Hodgdon lists 308 service data for IMR 4895 and a 168gr pill as

41 Start
44.2gr MAX.

I’ve read that 41-41.5gr is a match load.

Shot my M1a this weekend, and I’ve been trying to shoot lower than 41.5 as groups were not great at 40 nor 41.

At 42gr, my loads tightened up nicely.

I’m using mil brass and know the rule if lowering loads 1.5-2gr.

No pressure signs and tight groups!

Anybody else shoot an M1a that liked it hot?

Do does your…never mind. Don’t want to get banned.

Do you have any pics?  Has it been modernized/accurized/modified in any way.

The only modification I made was shimming the gas system and adding an oversized mag release.

The shims really made a difference.

That’s really not hot.

Great! Then I found a node on the warmer side.

If the max charge listed is 44.2, not sure why you're getting the vapors over shooting 42.0 grains.  Even subtracting the 1.5gr it still wouldn't be max load till 42.7, but I think both that fudge factor & (many) max charges are all on the very cautious side.

It’s my accuracy node is a little more than what people get with their M1a’s.


Also, Hodgdon used win brass which is 1-2gr more capacity than typical 308 brass and 1-2gr lower than 308 win data.

That’s a 2-4gr variance which now gets me near the window.

The Hodgdon service rifle data needs to be used with caution.

From the mishmash of CUP and PSI pressures listed, it is not real tested data, but computed from old 308 Winchester load data from different periods.

It looks like they just reduced by a certain amount or percentage of existing 308 load data.

Some of it might not be far off, but some of it looks fairly hot.

My scout isn't too picky, but my socom is. Using IMR4064 (this is over 155gr bullets mind you) with a start load of 37.9, it wasn't happy until 40.X. Hornady lists 43.2 max, so I guess it more in the middle than hot, we'll call it like warm.

40.5 grains of IMR-4885 is a maximum load in Lake City brass when using Winchester, Federal 210M (GMM) and probably CCI-#34 primers.

41.5 is a safe maximum in Lake City brass if you are using Remington 9.5's, CCI-200's or CCI-250's. These primers have recorded 6,000 psi lower pressures when using identical powder charges compared to Win/Fed 210M.

Without a chronograph there is no way if knowing how hot your load actually is. Apparently the newest 7.62x51mm brass coming out of Lake City, especially m118 LR, has more case capacity than the older m80 ammo.

168's traveling over 2550 fps from a M1-A is probably too hot. The same ammo will run closer to 2625 from a 24" bolt action and that's really pushing it with surplus brass.

Hodgdon uses Winchester commercial .308 brass for their load workups. Subtract 2.0 grains for Lake City surplus.

Rifles are made by people on machines from parts made by other people on machines.

They are not identical to each other even if they look like it.

Some rifles "like" different loads than other rifles.  Like - reliable and accurate with that ammo/load.  Best groups my M1A ever shot were with 180 grain Match Kings and powder you're not supposed to use in M1A/M1 Garand rifles.  I tried bullets by Speer, Sierra and Hornady from 150 to 180 grains.  I tried powders from IMR, Hogden and Winchester.  I used Federal and CCI primers.  That one load turned it from a disappointing rifle to a rifle that would put 5 holes in the paper my hand (fingers extended but closed/touching each other) would cover at 500 yds.  It also broke the op rod twice.

If you're rifle likes it and it's not showing signs of pressure, you should be okay (means you have to be able to recognize the signs of higher than normal pressure.)

Did you try an adjustable or vented gas plug on it?

Was it 4831 or 4350?

And Hodgdon data was developed with Winchester Brass.  A person has to look at the components used to make up the load.
And as I recall the M852 used IMR 4895 NON CANISTER GRADE (variances lot to lot is the norm) used 42 gr.  And, so I would
consider that max in LC M118 or M852 brass.

Case:Winchester
Twist:1:12.000"
Primer:Federal 210M , Large Rifle Match
Barrel Length:24.000"
Trim Length:2.005"
Bullet Weight
168 GR. SIE HPBT
Starting LoadMaximum Loads
ManufacturerPowderBullet Diam.C.O.LGrs.Vel. (ft/s)PressureGrs.Vel. (ft/s)Pressure
IMRIMR 4895Buy Now0.308"2.800"41.02,44739,700 PSI44.22,67353,000 PSI

It was 1982/83.  No internet.  No idea IMR4350 was bad for it till it broke the op rod again (first was bad luck?? , second was a stop sign) but I saw an article in American Rifleman a couple years later than explained all that.

And, never hear of adjustable gas plugs till years later, many years.  Have one on my M1 shooter rifle, never got around to getting one for the M1A.

Current IMR-4895 is a different powder, made in Canada, than the old US-made IMR-4895.

Some sources claim current IMR-4064 is closer to old, US-made IMR-4895 than current IMR-4895 is.

I started match shooting in 1981.

I started reloading match ammo in 1984.

My first load was very accurate and was 41.0 grains of IMR-4895 and I used the Hornady 168 grain hollow point, just because everybody else was using the Sierra.

A short time later, 42.0 grains of IMR-4064 became very popular.

Federal had been contracted by the Marine Corps shooting team to load 39.0 (or 39.5) grains of IMR-3031 with a 168 grain SMK.

This became popular with other military teams and federal agency teams.

Federal wouldn't sell the load commercially.

Around 1990, match shooting had become popular with the imports of M1 Garands and M14 parts and Federal developed a full power 308 Winchester commercial version of the Marine Corps contract match load.

They used the same components, but increased the powder charge to 41.0 grains of IMR-3031.

This was make it a full power load and an effort to prevent other companies from making a full power load before them.

It was very expensive ammunition at the time.

Later, Winchester, Remington and then Hornady came out with their match ammo.

Federal changed the powder to 42.5 grains of IMR-4064 as the traditional 42.0 grains just wasn't hot enough.

Then Federal and Alliant Powder became owned by the same parent company.

There was a desire to use Alliant powder in Federal ammunition.

The Gold Metal Match load became 43.5 grains of RL-15 with a 168 grain SMK.

This load wasn't liked very much and the other companies had some hotter match loads.

Federal then went back to IMR-4064, but with 43.0 grains of powder.

The Federal M1A ammunition uses a 168 grain open tip match bullet, made in-house by Federal, a #34 primer and 42.5 grains of IMR-4064.

One day I had a both Gold Metal Match ammo and the M1A ammo and a chronograph available.

With my M1A I got exactly the velocities from both.

I measured the powder on my scale and measured 42.8 grains of IMR-4064 in both loads, of the two cartridges I broke down.

Varget works great in 30-06, but can produce too much gas port pressure in 308.

H4895 can load hotter loads than IMR-4895 and still not over-gas the M1A.

I’m also .6gr over Hornady 9th and 10th MAX.

Some of the Hornady 168 grain load data includes the Amax, which is longer than the hollow point.

When I started reloading, Hornady showed a maximum of 39.5 grains of IMR-4895 with a 168 grain bullet.

Also 40.0 grains of IMR-3031 though.

The Sierra manual had a maximum load of 41.3 grains and I was loading 41.0 grains.

The heavier bullet gave more felt recoil than M80 ammo, so I didn't want to go any hotter.

Some years ago I contacted somebody at Hornady and was told that certain maximum listed loads weren't always maximum loads, but sometimes where they stopped loading that powder, either due to lack of accuracy, ran out of that powder that day or for no reason at, such as returning from lunch and starting with a different powder.