My first precision rifle

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rugbydave

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I started amassing the kit I'd need for a precision rifle over the winter. I've been shooting my M14 as a long(ish) range rig for years now and it's served me well. It'll hold 1.5 MOA with my hand loads and I shoot it as far as our range goes (475) weekly. I'd been wanting something that would hold a tighter group though so as to push it out further and hopefully take a LR course and try a competition. So far I have a Rem 700 AAC-SD in .308 with a 20" 1/10 twist barrel tipped with an Insite Arms Heathen Muzzle brake bedded in a Boyd's Pro Varmint stock with a 20 MOA Badger rail and a Rifle Basix trigger. She's currently sporting the Leupy Mark IV that normally sits on my M14 so that I can do some load development before I get a new scope and rings (hopefully this week!).

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I was out doing some load development yesterday. 178gr Amax over Varget in PRVI cases with CCI 200 primers. I worked my way up from 41.0 gr to 43.0 gr in .5 increments. All seated at 2.807" except the 43.0 gr load as it was compressed and I could only seat it at 2.822". That load had an average velocity of 2545fps with an ES of 16.59 and a SD of 6.16. It grouped at 0.84 MOA. Not too bad. The whole point of this session was to see if the rifle could group, period, since I had never shot it. It wasn't bad with the tightest being 0.73 MOA and the worst being 1.20 MOA. I'm going to do some ladder testing next at 200 yards. I was wondering if I should just seat everything at 2.825" and see if I can get step up to 43.5 or 44.0 grains, eke out a bit more velocity? Any thoughts? Here are the targets. For what it's worth, it was quite gusty yesterday, haha.

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41.0gr:
MOA: 1.02
Avg vel: 2386fps
ES: 23.48
SD: 8.88

41.5gr:
MOA: 0.73
Avg vel: 2432fps
ES: 44.75
SD: 18.00

42.0gr: (the 1st 2 rounds of this string failed to read on my chrony so these numbers aren't very accurate/representative)
MOA: 1.20
Avg vel: 2502fps
ES: 15.03
SD: 8.36

42.5gr:
MOA: 1.02
Avg vel: 2507fps
ES: 14.54
SD: 6.0

43.0gr:
MOA: 0.84
Avg vel: 2545fps
ES: 16.59
SD: 6.16

Sorry for the glut of information and thanks for all advice/help!
 
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Why did you start at 2.807"? and then why did you switch to 2.822. I mean I know you did it because of powder compression, but why 2.822" not anything longer.
It would be good to know what your overall length is when the bullets are seated touching the lands, and what your mag length is?
 
Set OAL to the longest length that will fit in the mag and feed... and not jam into the lands.

The bottom target with a single group look very promising. If this is the highest load of 43gr, I would test 42.6, 8, 43.0 and 43.2 at 200 to 300yds.

See how the groups and vertical go.

Enjoy

Jerry
 
I was aiming for 2.805" but with the variation in the tip length of the Amax and not having a means of measuring ogive to base, the average worked out to 2.807". I loaded the last at 2.822" because that's as short as I could get it with that load of powder and I tried it to see if it would load and chamber and it did. I was just trying to be conservative and stick to close to the suggested COAL but I'll have to get in there and see just how long I can seat them and have them fit and feed from the internal mag without being jammed in the lands...

I'll be retesting at 200 and 300 for sure, Jerry.
 
I believe the factory BDL mag is around 2.825" max OAL and you'll find your lands way beyond that in factory Remington chambers usually unless they changed recently. AI mags or an extended mag box is the only way to get out to your lands and still feed from a mag and even then you usually need a heavy pill to seat that long and still have enough bullet in the case. In your case I would decide between 2.8, single feed or AI mags.
 
Sometimes dropping the powder into the case with an extended drop tube will give you more room for seating. Friends of mine running the 190's in 308 love their drop tubes. I decided to switch to 8208XBR for more room with the 178/175's

I'm loading 178 Amax to 2.820" avg
 
Please use caution, but less lawyed reloading books (of just a few years ago) had Varget under 175's max limits around 45.0C.

I find many 308's love 175's at around 44.8-45.0gr Varget.

Compressed loads are common with certain powders. Crunch away.

As always, PLEASE WORK UP TO SAFE LOADS, and take all information on the internet and triple check other resources.

175's can often go 2700+ FPS (with a 20" barrel)
 
Might sound dumb, but try putting a piece of heavy outdoor carpet under the bipod. I bet that will tighten up the groups. If it doesn't right away. Try loading it up a little bit. The bottom left group on the first target and the single group look good. I'm thinking maybe a little work on position will tighten up the horizontal dispersion.
 
Thanks all! The rings are high for sure, that scope and ring combo belongs on my M14. The new rings I get will be nice and low. I'll have to order myself one of those drop tube funnels. I measured the length of the internal mag and it's 2.8365" so I'll try and see if it will feed at 2.835 and see where it is in regards to the lands. I'll try some carpet under the bipod and work a bit on my position. I honestly don't shoot much from the bench (pretty much only when working up a load) and normally shoot from prone. I figure things should tighten up as well as I get used to a different trigger, etc.
 
rugbydave said:
Thanks all! The rings are high for sure, that scope and ring combo belongs on my M14. The new rings I get will be nice and low. I'll have to order myself one of those drop tube funnels. I measured the length of the internal mag and it's 2.8365" so I'll try and see if it will feed at 2.835 and see where it is in regards to the lands. I'll try some carpet under the bipod and work a bit on my position. I honestly don't shoot much from the bench (pretty much only when working up a load) and normally shoot from prone. I figure things should tighten up as well as I get used to a different trigger, etc.
Click to expand...

If you normally shoot prone then forget the bench, go with what you are used too and most comfortable with.
 
Some good comments here. To add I would say that do load development at 200m if possible - 100 gives too many 'false positives' and 300 sometimes produces too much 'user error' data. The other thing is that you should figure out what distances you will most frequently shoot at - a low node may be all you need; no point in finding the perfect 1000 yard load when you will only ever reach out to 300.
 
So went out yesterday and did some 2 round ladder testing at 200 yards. There was almost no vertical at 42.0gr then starting increasing to a lil over an inch before coming back down to sub 0.5" at 42.8 and rose again before dropping down to less than 1/3" at 43.5 and 44.0. I had to single load everything 43.5 and up. I wish I had just shot 3 round groups but oh well.

I went back today and shot some 3 round groups. The best groups 0.628 MOA (42.8gr) with almost no vertical (about 0.373") and 0.778 MOA (43.0gr) but with 1.326" of vertical. The strange thing is that the the numbers for the 42.8gr load sucked (ES: 39.65 SD: 19.97) whereas the numbers for the 43.0gr load were stellar (ES: 8.43 SD: 4.35). I'm not really sure what accounts for that? The higher powder charges really didn't perform, for whatever reason. They were all above 1 MOA and were mostly vertical. The ES and SD for them were also horrid. I'm not really sure what was at play there. I'm fastidious about my reloading practices, I averaged it out over the past month and my ES and SD for my M14 ammo are 26.6 and 10.5 (9x 5 round groups, full length resized). The groups I shot above 43.0 today had a ES/SD from 37.85/20.07 to 78.16/39.01 ( 3 round groups, new brass that was neck sized). All I can think of was I held the charged cases on my vibratory tumbler before loading the bullet and was thereby able to bring down their COAL to about 2.827-9 and was able to load them in the internal magazine. They all fed well but I'm thinking maybe they were rubbing on the front of the magazine before being chambered and things were somehow upset?

In any case, I think I'll opt for that 42.8gr load until I install a dbm in this rifle. With the averaged out MV (2519fps) I have for it, JBM tells me it'll be subsonic after 850m and transonic after 700m. Hopefully the 178gr Amax transitions decently through the transonic range? I'm hoping to push this rifle out to 800m or so so I guess we'll see. I'll work up a stouter load once I install a dbm and can load the rounds a lil longer. Thanks for all the advice!
 
And why I suggest you test as far as you can. Chronie numbers do not always reflect what is best for the barrel. In theory, it should but as you have found, reality has a mind of its own.

By testing as far out, you give the bullet the chance to disperse. Yes, velocity variation is supposed to be an indicator of that but... see above.

At 300 to 500yds, anything that is going to happen WILL... now testing in 0.1gr increments yields the best results. Pick an OAL that works... forget about jumping around unless you want to retune your load again.

Use a drop tube.. Forster makes a good one.

At the furthest you can test in calm air WITH flags, test 42.7, 42.8, 42.9 and 43gr. Do 2X4 rds groups or larger sample size... entirely up to you and your ability to be consistent over long strings of fire. Watch barrel heat and track any dispersion related to barrel warping.

Do final testing with fireformed brass only. New brass WILL create irregularities in your load tuning.. case expansion is inconsistent which can affect groups and velocity readings. Many competition LR shooters will only use brass that has had at least 2 full pressure firings... yes, it matters.

At some point, you will find a load that is both accurate, consistent WITH stable velocity numbers. Maybe the ES and SD aren't internet perfect but small groups way out there is the point of this excercise.

Enjoy and good luck.

Jerry
 
Shibby! said:
That's the lower "node". Very accurate but when you need velocity, it doesn't cut it.
Click to expand...

2650 fps from a 24" barrel. It is probably pretty slow as far as handloading goes but I think it's better than some factory ammo. It's fast enough for me anyways.

OP where did you get the elastic two round shell carrier? I see those on everyone's rifles bit I can't find then for sale anywhere.
 
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