SA20 Accuracy

Longshot338

Longshot338

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Hello GunNutz,

I am going to the range tomorrow to do so load development. I am trying to find the load that my SA20 likes most for accuracy. I am also trying to find where the max pressure point is for my rifle.

I am loading PPU casings. They have been sorted, trimmed, chamfered, deburred, de-crimped, and had the prime pockets uniformed.

I am loading Hornady 68gr HPBT bullets.

I am using Hodgdon BL-C(2) powder. I h started at t minimum, an worked up in 0.5gr increments up to 1gr past max (according to the books)

I have 2 questions?

Wh sort of accuracy will I realistically achieve with this rifle? Is it a 2MOA rifle? If I get 2MOA, should I expect that it can be better an keep developing loads, or do I assume I have hit this rifle's maximum potential? What should an SA20 with handloads be able to shoot?

Secondly, what do I look for in pressure signs with an AR15? I know what to look for in a bolt rifle, but how do I know when I have hit max pressure in an AR15?

Thanks guys,
Alec
 
Fired carefully from sandbags with a decent optic, it should be capable of less than 2 moa. Lots of variables.
As you work up through your loads, you will probably see increasing primer flattening. Do you have a micrometer to measure case head expansion?
.223 can be a bit tricky. There may be a fine line between a hot, but safe load, and primers falling out.
It is also February. A load that might be just fine now could be way too hot in July.
 
I'm waiting on a scope for mine, but iron sights are consistently printing right around 2.5" groups, and thats with not new eyes.
 
You've got the rifle, you're doing the development, you'll be the one shooting.
Instead of asking what to expect, go shooting and show us what you did. You sound serious, so I'm sure you'll do well.

My only suggestion is that .5 increments may be too course.

Aside, my prediction is the best group of your life, coming in at 1.3moa :).
Happy shooting.
 
Mine shoots consistently sub 2 MOA with factory loads. Mostly somewhere between 1.5-2, but sometimes I get lucky and get an MOA group.

This is with an Elcan C79, using various 62gr green tips (PMC, Federal, and IVI) off of a bipod, no rear bag.
 
Not a SA20 but a SA15.7. I've managed to bang a 4" plate at 200yds all day long with an ACOG on top using a wide variety of green tip. With 75gr. and 77gr. OTM the rifle will shoot about 1-1.5 MOA if I do my part, making solid hits 80% of the time on a 10" gong at 500 yards from a sitting rested position.
 
I do have a micrometer. Do I stop shooting at the first signs of expansion?

I will look at primers as well to warn me when I am getting close. My experience with bolt guns is that a flattened primer comes just before max; but you can still push it a little bit beyond the stage when the primers start to flatten.

I am still in the first stages of load development. Once I start to see where the rifle likes the powder charge, I will go up and down from there in smaller increments.

After that I may try different seating depths; though I am so far off the lands in my rifle even at max mag length I don't think it will make much difference...

I do adjust my powder charges for warmer/cooler weather.

As for the sand bags; my barrel is obviously not free floated. Should I be resting the front of the rifle near the tri rail on the bag, or the rear of the hand guards right in front of the magwell?

Thank you for the input so far!

Alec
 
I don't have pics but I developed a load out to 300 m which gave me about 1 moa
Shooting off a bag. This is the load
IVI brass
25.3 gr of Varget
69 gr SMK
CCI BR primer
Seated to mag length

I going out soon to try it out again. I've acquired some BLC-2 with Hornady 68 HPBTs so it should be interesting what you might achieve with your load
 
I brought my CC Sa-20 upper over the shooting team last summer. I did zeroed it and fire it for 2 days with IVI ammo. But remember I shot the thing prone mag on the ground. No sang bag and no other support. I had my ELcan C79 on top of it. THAT one in this condition is 1.5MOA. Not better. Perhaps in a vice or a bench it could do better.

Maybe a match reload will get close to 1 MOA also. I did not test any reloads in it.

Cheers.
 
If you are using a decent scope and a decent rest you should be able to get close to MOA or better. Not sure why you would load over book maximum. Unless you are a knowledgable, experienced reloader you should NOT be running over book max!
 
Load testing was not happening today. Winds were gusting 32knots today.

I did sight it in with the minimum charge loads. In doing so, I shot several groups under 2 MOA. I did not shoot any hotter loads; I will wait for a better day. I could barely keep the paper on the target never mind calling a consistent condition to shoot in. It also didn't help that the ground was too frozen to stake my flags in.

I suspect at least 2 groups came in around 1.5MOA. Unless I have already found the optimum powder charge at 23 Grains, I suspect I can do better.
 
Every chamber is different. Different companies use different reamers, ream to different depths, etc. Batch lots of powder can be different. A different style of rifling produces different resistance on the bullet.

For example; you can be operating at max pressures with a given load. Switch to a different batch lot of the same brand and type of powder, and you could be well over max.

Try using data for your 6mm cartridge of choice in a .236" Krieger! Most 6mm barrels are .237" if I am not mistaken. Krieger offers one in a tighter bore. You get that barrel chambered in a round you are familiar with and all of a sudden your minimum load could become your maximum!

Reloading manuals are GUIDELINES! Every one of them will tell you to start at the bottom and work upwards.

A perfect example is my 243Win. I have gone up to 1.2gr over maximum, and I haven't encountered even the slightest pressure signs.

I am neither claiming to be knowledgeable or experienced. However, I know how to safely find out where maximum chamber pressures are.

It is far more foolish to reload blindly. Next time you go to buy a pound of powder at your LGS, are you going to check the batch lot #? If it is different, will you start at the bottom and work up to your known load or will you blindly trust the powder company to produce consistent batches of powder?

8 ball said:
If you are using a decent scope and a decent rest you should be able to get close to MOA or better. Not sure why you would load over book maximum. Unless you are a knowledgable, experienced reloader you should NOT be running over book max!
Click to expand...
 
Longshot338, you obviously had a good handle of reloading. Consider getting a Hornady manual or any that offer loads specific to 223 Service rifle.

Given the similarities in AR's, it is a good baseline to compare velocities and charge weights.

I would suspect that within 50 to 100fps of printed velocity with similar barrel set ups, your loads are within reason. Over this and you are on the hot side.

WRT to the Kriegers 6mm bore sizes... yes there are 2 and they offer the match shooter options on how they want to set up their rifles. 236" bore is not bad nor is 237" bore good. Just another spec like twist rate. There are a number that use the 236" for match shooting and do very well.

Jerry
 
Jerry,

I was actually basing my start and max loads on the Hornady 8th edition 5.56x45mm chapter.

I also have Berger, Nosler, Barnes, Speer, Sierra, and Lyman manuals plus the Hodgdon website. I cross reference all the time. If I am shooting Berger bullets, I use the Berger manual. If I use Sierra bullets; the Sierra manual. They also give me different powder options.

I have also found contradicting data. When I first started reloading, it was 303 British for my Enfields. I found one manual where the max charge was listed as less than the minimum charge in a different manual for the same bullet and powder. Talk about confusing for a newbie!

As for velocities, I don't own a chronograph. I read my brass signs and look for signs in the rifle (bolt being hard to lift, ejection patterns, etc...)

I don't own a precision rifle. Mainly Enfields, M14's, AR's. I have an old Rem700 in 243 Win that shoots better than it has any right to with a factory barrel.

My father-in-law is a benchrest shooter. I shoot with him every time I visit. He is a wealth of knowledge. I take what I learn and apply it to my rifles. Within reason of course; jammed bullets and neck turning don't belong in a battle rifle...

I was using the Krieger as an example of where a minimum load could be quite high in pressure. I don't actually have any experience with a 6mm Krieger other that a bench rifle that isn't mine...

Thank you for the valued input. Your experience is always of value to me and the other shooters on this forum.
 
Well the results are in!

As mentioned previously; I didn't test or develop any loads today due to the wind. I had 25rds of the minimum charge cooked up for sighters/foulers and just having fun.

The three groups I fired measure as such: 1.424", 1.241", 0.938".

I am quite pleased with this. When I hit the range on a less windy day with wind flags that will stay in the ground I will begin working through the powder charges up to whatever my max may be.

I will keep you posted!

Alec
 
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