Reduced load accuracy?

[brotherjack]

Just curious as to what experiences people have had with accuracy and reduced loads (in my case, using a 308 Win, looking to make 30-30 to 303 British like velocities) - has accuracy been better, worse, or approximately the same as full power loads?

Thanks,

 

[curtmg]

Not quite the same, but I'm going to be shooting off 50 reduced loads in my 300WM on wednesday. I'll let you know how that goes, 180gr bullets, at what the manual says should be ~1800 fps, as opposed to the more typical ~3100. Unfortunately I don't have a chrony, but I can measure groups and compare.

 

[ben hunchak]

My reduced loads of cast bullets in the .308, .300 Whisper, and 30/30, are more accurate then top-end loads with jacketed. In all fairness, the accuracy did not come right away and it takes alot of experimenting. All bullets are hardcast gas check design and pushed from 1058fps in the Whisper to 2100 fps. in the .308 Win....powder charges range from 7.5grs. in the Whisper to 19.5grs. in the .308, seating depth is critical for accuracy such as this.

 

[JasonYuke]

Accuracy comes from a number factors I have done much reading and reseach ( my own ) with different cases and calibers on this very issue.

My main down fall was I read too much in the past and just did not try it for myself.

The combination of case powder bullet as I see it is all you have to work with once you have a new custom, or factory barrel Built)to play with unless you want to tear it appart and send it for tunning.

Not to go on in too much detail, of the construction and assembly of the action, bedding, headspace, and over all trueness of the action, and barrel are all factors that will allow your gun to shoot at different nodes as I will explain.So the bottom line here to point out a good shooting rifle should hold suficient but not percision accuracy if put together right. The harmonics are should say used friendly!!!

But a picky fussy rig, which we have all owned one, may spray for you at the low node.

What I have found in general is the more full, loose terms you can get your case (90-95%) case capacity you will find your top node when I say this that is the node that the bullet,powder,case works best at that tuned to the harmonicly to your barrel and your barrels happy place. By adding and lowering the powder you change the speed and vibration of the projectile changing the effect in velocity changes the harmonics of the package deal changing the std dev to big numbers.
I found on all my rigs 2 ppc, 6pps,6mm BR, 308s, 6.5s, and even 222s the top node works best.

However when lowering your velocity in most cases you will find a lower node, maybe 5 maybe 7 grains lower the rifle will tell you...

In all my tests I found the higher node to be more predictable than the lower for the simple fact the case has more powder. Powder can do many funy things durring the burn if laying flat or shoved mostly to the front end of the case.. specialy in low powder charge cases, or low charge density cases of 80-85% i would not use lower charges the burn rate will be speratic and can be dangerous if under charged in a slow powder. That is why fillers sometime need to be used to hold the powder in to a rear compressed state or colume. Fillers can have or add pressure issues with powders. Not something to fool with if you do not understand it.

You can do a ladder test to find a reduced load and maybe a new node of harmonics for your barrel.

That is why pistol powders are made so fast for low density burns.

I thing remington is not telling the true storry about the reduced loads, I think they must have found a new powder that is bulky and allows a high density but a low pressure for the loads.

However powders like IMR 4959 (bulky) at low charges produce low velocity and PSI and work quite well in modern cases with lead bullets. But this gives you balck powder velocity to 1200 to 1600 fps in some cases.

However saying this there are many cases you can lower quite low and still have sufficient hunting accuracy in the 1.5 to 2 inch mark.

Thats all I know likely forgot to mention a few things.

Now to answer your quesion my 308 shot like crap at 100 yards vs a full load .5 moa group with full loads. Veyr un predictable 2-3 ich groups maybe even 4 at times.

And I have had good success as you mentioned with teh rimmed cases like the 30-30 and 303 with reduced loads and lead!

Regards

 

[H4831]

Much depends on the powder. Most slow burning rifle powder, like that used in full power loads, burns very erratic at lower pressure. Note that competitive bench rest shooters operate with full case loads of powder that gives them more pressure than most of us use for hunting loads.
Usually, fast burning powders in greatly reduced loads are used for light loads. They burn fast and create high pressure, for a short while. An example is the 44 magnum. Full power loads are in the vicinity of 1500 fps. A very good light load is about 10 grains, well under half a case full, of W231. This generates about full pressure for the gun, but gave a velocity in my 7½ in. Ruger of about 1000 feet per second and was a very accurate load.
Many years ago the US military developed a light load for their 30-06 service rifle that won world class matches where ever they went with it. I forget the grains of charge, but the powder was the old Hi Vel #2 and the velocity for the sevice bullet was 2200 feet pear second.

 

[JasonYuke]

H4831 you hit it right on thats all i needed to say, Is use the right powder for reduced loads, and you will be fine.

It would be neat to find that old Match load you suggested. Be intresting to see what they used for powder. 4064 comes to mind but they had some different stuff back in the day!

 

[hs4570]

Reduced loads

Have done up/tested a lot of reduced loads for about 8 different calibers usually useing pistol/shotgun powders as the purpose is not for reduced recoil but reduced velocity for grouse/ varmints / finishing shot and the like.
This is in the 1200 to 1800 fps range depending on caliber...and the criteria is that it shoots to point of aim from 25 to 50 yards while the rifle is sighted in for its regular hunting load.

While doing these loads I also went with good reduced load rifle powders like IMR4227 and IMR4198 that I had on hand. In .308 these would be called " inefficient " in that they peak out in pressure much faster and with much less velocity than the other IMR .308 standard powders/ loads combinations.. with high velocity.

In the "DuPONT" Imr booklet that they have published in the past and gave out free... they list every powder they make and what the max. load is with every powder in most standard bullet weights and hunting calibers including the .308.

In .308 win.

110 gr Hornady spz....32.0 Gr IMR4227 max...2835 fps...51,900 Copper Units Pressure (CUPS)
150 grain Rem PTD.....26.0 Gr IMR4227 Max...2260 fps...51,100 CUPS
IMR 4198..................35.5 Gr....2595 fps......51,300 CUPS

180 grain Rem. PTD....27.0 gr IMR4227 MAX..2110 fps...52,000 CUPS
IMR4198...................33.5 gr IMR 4198 Max.2350 fps...51,600 CUPS

So I started at 2 grains less than max with IMR4227 and worked backwards to where I wanted to be ..velocity wise ..and found excellent accuracy throughout the downloading process...especially with the 150 grain loads.

My requirements were met at 16.0 grains IMR4227 useing a Speer 150 spz flat base at 1530 fps..1 inch high at 50 yds with a 0.360 inch group. This was later tested and although low at 100 yds shot 1.10 inch group out of my 18.5 " 788 Rem .308.

Useing a 180 gr.Rem spz. FBase and 20.0 gr IMR4227 at 1650 fps this shot just as well as the 150 grain load..cloverleafing at 50 and one inch at 100 yds on later tests.
I had good success with this powder in my 30/06 also at close to similar velocities.

I have used IMR4198 in many other than .308 WIN. for reduced loads and it worked just as well and feel that the (23-2450 fps).. higher velocities you are looking for would probably be better served with IMR4198 working backwards.....rather than slower velocity IMR4227.

Useing only IMR4198 I have 4 other calibers that will shoot greatly reduced velocity loads at the inch at 100yds....so my experience with reduced loads has been they are quite accurate.. once you find the bullet and reduced velocity your rifle likes them at..

 

[blacksmithden]

I've been punching 200gr cast bullets out of my 300 win mag using 14 grains of Unique powder. If I haven't had 14 cups of coffee on the way to the range, I can repeatedly get 1.3" groups.

I can tighten that up a bit by using a full charge and a 180 grain jacketed bullet, but not by much.

H4831 hit the nail on the head. Reduced loads work better with a faster powder. Full pop magnum loads require a slower powder for accuracy and a more drawn out pressure curve.

 

[sbtennex]

Here`s a good one for you .45-70 lovers: 2.3cc or 16-16.5 grs Blue Dot shotgun powder behind a 300 gr jacketed bullet - right around the speed of sound, accurate and shoots with a ``crack``. Great plinker. No filler, just load èm muzzle up in the levers.

 

[H4831]

Jason Yuke, I did actually say the powder, it was the old Hercules, Hi Vel #2. Here is a copy from the 1962/63 Elwood Epps catalogue, of the powder. I left the add for 2400 there, also.
The loads I referred to were military loadings, so wouldn't know the amount of powder used.

 

[curtmg]

Just back from the range with my reduced loads for my 300WM. From 31-33 gr of H4198 in .5gr steps. It looks like 32.5 will be the best load. Other than having to adjust my scope 15 inches up, and 3 to the right(?), they were splendid for accuracy. I'm certain they'll be the perfect load for me to get a lot more trigger time on the big gun. There was less recoil than my 22-250 I just bought from my buddy. My main motivation for making these reduced loads is to increase my trigger time, decrease my pain, and to help learn to shoot better. After I fired off 30 or so of the reduced loads, I found I was able to transition easily back to the full power loads, and actually was able to keep my eyes open when firing, something I've not been able to do until today, with that gun. I've put about 5 bricks through my 10/22, but I found this to be a lot more valuable practice, as it's the same gun I was having trouble with, being fired in a much gentler fashion.

Just to be fair, I also must admit, I jammed 5 lbs of lead in the stock of the gun, to make my 8lb gun into a 13lb gun. So that contributed considerably to the reduced recoil, I'm sure. Now my next task is to free float the barrel. I'm told I just need to take a dremel, and take a bit off of the stock (stevens 200 plastic), if anyone has any advice on that, maybe PM me if you want, but I'll be checking the gunsmithing section for more advice on the matter before I proceed. Thanks