AR2207 reduced load under a 168gr 308w

[tattless_tradie]

Hello peeps - long time lurker, first time poster. Now I realise this is technically NOT an F-class question (I'm a regular Service Rifle and TR shooter), but you guys sure know your stuff when it comes to ballistics. If I get zero response, then I guess this is why (which I'm cool with). Be gentle if you choose to engage

I'm searching for a low-recoil load for a m1895 Mauser Carbine 308w for service rifle shooting. My understanding is that AR2206H is the go-to powder for reducing loads. With AR2206H, it's a no-brainer; just start at 60% and work up from there. The trouble with this is that (especially given the short 17.5" barrel) the amount of propellant burned is under 90% (according to Quickload).

I currently am running a 125gr pill over a 70% fill of AR2207 (33gr to be exact), yielding an apparent pressure of 37kkpsi according to Quickload. It's a better load for the little carbine as it's 100% burnt and recoil is just sublime. I want to keep pressures south of 40kpsi due to the antiquated action. For the 308w, listed data only covers up to a 125gr bullet for use with AR2207 powder - nothing heavier.

Now I am out of 125gr pills and want to start running some heavier 168gr FMJs (I have tonnes of them, which need using up). I was tempted to run 30gr AR2207 under the 168gr which according to Quickload is in same pressure region (South of 40kpsi). The trouble is, there's no listed data or information anywhere about reduced AR2207 + heavier FMJ bullets. Furthermore everybody recommends AR2206H for reduced loads under normal-weight 308w pills - that or Trail Boss. I've used AR2207 under 168gr lead 30/30 bullets in the past, but understand lead bullets are "slipperier" compared with jacketed, so comparisons cannot really be made.

QUESTION: is the use of (a comparatively reduced 62% charge of) AR2207 under the heavier 168gr FMJ as catastrophically dangerous as everybody is saying? Why is AR2207 so much less appropriate than AR2206H for this application? (given I've crunched the numbers in Quickload and gone down with the AR2207 charge in conjunction with the heavier pill). Should conventional wisdom be strictly adhered to here? I thought generally faster powders could be reduced as-safely as AR2206H, provided the charge wasn't too high, and volume is >60% preventing a "secondary detonation"...

Go easy on me - I'm still learning.
Cheers.
Tattless.

[Tim L]

Reduced loads isn't really my thing and you're trying to tackle problems I've never considered, but I imagine the concern is going to be the risk of secondary detonation.
I generally try to use a powder that fills the case (for a number of reasons). You're going a tiny bit slower with 07, What does quickload say about 2208 an 9?
Its slower again so might not all burn in your short barrel, in fact 09 might not even ignite.
I'm only suggesting this because personally I wouldn't want to be too close to a gun running 62% fill. Secondary detonation is devastating. I'd rather have a bigger safety margin between me and that outcome.

[tattless_tradie]

Thanks for the reply Tim. Actually AR2207 is faster than AR2206H - nearer Bench Mark 1. I always thought you could “go faster” than AR2206H (but not slower) when reducing. Maybe I am misled.

[Cliff Austen]

Take Tim's advice.
Go to the ADI data on Rifle Reloading. You will see the minimum load is 39.9 grains of 2207.
DO NOT underload your cases. The last thing you want is secondary detonation.
Stay Safe.
Cheers
Cliff

[RDavies]

You mentioned trailboss. How low did you want to go with velocity? I got pretty good accuracy with about 15-16gns of Trail boss behind 168 Sierras in my 308 for around 1600 fps in 26"" barrel. This was a full case of the very bulky powder, but recoil and noise was much lower than with regular full power loads. We used it as a plinking load for when the kids were younger, but I do remember accuracy was good even out to 200-300yds

[superx10]

Don't some of the big ammo manufacture's make reduced loads for the 308 and the 300 Black out for use with suppressors so as to mitigate noise?

[GregW]

There is a simple solution to this dilemma. Load your selected amount of powder, then top up the case with pollard. (chook feed)
This means the powder remains as a cylinder and burns as it is meant to. This was fairly common practice in years gone by.

Greg W.

[tattless_tradie]

Thanks for all the feedback guys. Much appreciated - I know SR is probably not really the forte around these parts.

Cliff with your suggestion:

Go to the ADI data on Rifle Reloading. You will see the minimum load is 39.9 grains of 2207.

you must be referring to a 110gr projectile? That's pretty hot - I'd be scared to run that through a m1893 action. The problem I'm trying to solve here is "how safe is a reduced load of faster-than-AR2206H powder like AR2207 under a heavier 168gr .308 projectile" (considering this is outside of listed zones).

RDavies: yeah i've run TB in the 308w before. Personally I'd be scared to go above 14gr under a 168gr in the old 93 action - even though TB is "fluffy" so to speak, it's extremely fast-burning. Pressure spikes quickly with additional powder. I will come back to this down the track - I think it will work fine for 100m offhand matches. But I think it'd be hard to use from the prone mound with swirly wind. I'm keen to keep the one load for all distances, for walkdown-style events.

superx10: yes it's a thing. But I haven't bought factory in years. It's bloody daylight robbery! I guess I could pull one apart, if that's what you mean. I bet it'd be winnie ball powder though...

GregW: yep it could work. But the novelty of handloading has long since worn off for me - looking for something nice and convenient, for quick-n-cheap weekly turnaround.

I ran 33gr of AR2206H under the 168gr for a match on Saturday. Accuracy was good, but recoil was a little stiffer than 33gr of AR2207 under the 125gr. However, interestingly, barrel heat was notably cooler with the AR2206H load. Guess the lighter pills+faster powder scream out that bit faster? I spoke to a couple the older chaps and they tended to agree that it'd probably be safe to run (a reduced >=65% charge) of AR2207 under the heavy, because AR2207 is faster than AR2206H - the secondary detonation risk is understood to be an increasing risk the slower the powder, provided case fill is >60%.

[mike H]

Tattles ,
I am with you using 2207,this is based on loads from the IMR Handloaders Guide which has a load for a 180 grain Remington PTD SPCL bullet,Remington case, Remington primer,,2.75”COL giving 2350 fps@ 51,600 CUP of pressure with 33.5 grains of IMR 4198.
Now 2207 is H4198 and whilst you can’t say they are the same as IMR 4198 they would be close.
In the Lee Modern Reloading,Second Edition they appear to have the same data,but show that load as maximum and have a starting load of 29.7 grains with a velocity of 2117 fps.
Chapter 9 in that Lee book is worth studying
All the best.
Mike.

[tattless_tradie]

Tattles ,
I am with you using 2207,this is based on loads from the IMR Handloaders Guide which has a load for a 180 grain Remington PTD SPCL bullet,Remington case, Remington primer,,2.75”COL giving 2350 fps@ 51,600 CUP of pressure with 33.5 grains of IMR 4198.
Now 2207 is H4198 and whilst you can’t say they are the same as IMR 4198 they would be close.
In the Lee Modern Reloading,Second Edition they appear to have the same data,but show that load as maximum and have a starting load of 29.7 grains with a velocity of 2117 fps.
Chapter 9 in that Lee book is worth studying
All the best.
Mike.

YES this ^ thank you Mike that's some real data, the kind I was looking for. Quickload more or less spits this out. 33gr under a 168gr would probably be close to maximum safe pressure in a MODERN action. Even still, I'd be pretty hesitant to shoot it, even in some tacticool thing. I was thinking around 29-30rg under the 168gr should keep it south of 40kpsi, while still being >60% fill, for my little m1893 carbine.

[tattless_tradie]

Tattles ,
I am with you using 2207,this is based on loads from the IMR Handloaders Guide which has a load for a 180 grain Remington PTD SPCL bullet,Remington case, Remington primer,,2.75”COL giving 2350 fps@ 51,600 CUP of pressure with 33.5 grains of IMR 4198.
Now 2207 is H4198 and whilst you can’t say they are the same as IMR 4198 they would be close.
In the Lee Modern Reloading,Second Edition they appear to have the same data,but show that load as maximum and have a starting load of 29.7 grains with a velocity of 2117 fps.
Chapter 9 in that Lee book is worth studying
All the best.
Mike.

Actually I couldn't find the data you referred to in the Lee Modern Reloading,Second Edition. I'll see if I can source a copy of IMR Handloaders Guide - until then, pausing this (and just running AR2206H).

[mike H]

It is at the bottom of page 430 in my book.
The IMR Handloaders Guide,I found a pdf copy on google which was as clear as Crystal to read,there were plenty of various DuPont Handloaders guides for sale on eBay as well,not that I wanted to purchase one.