FN SCAR 17 Load help

[infidel 811]

After going to the range, I took 3 5shot groups was not so happy....every 5 shots I had 2 fliers. 3 shots were about 3/4 moa. its 9Degress F out this morning with a 3mph L to R wind. I used all steps to make brass and loads ALL the same. some of the LC brass is from diff years only thing I have not checked is case weight. im wondering if its me shooting? or the imr 4064 in cold weather, or seating (2.797) or scope (vortex 1x5) dang im going nuts now and my brain wont stop turning. 44gr seems to be the correct load(powder) any help or wisdom would be awesome!!

set up:
scar 17 (308)
Lake city brass
cci primers
imr 4064(44gr)
168gr hornady hpbt

Using single stage press, rcbs AR dies with crimp.

 

[Canadian Bushman]

There is a lot that can cause flyers, its hard to say what it is in your case. Let me ask a few questions.

What did you find as a max load during work up?
Whats the average achievable accuracy of you and that weapon, and what ammo was used?

 

[300WineMag]

Infidel 811

I have a Scar 17 and have tried a few different types of bullets and powder weights, all with 4064 powder also. 168 SMKs, 175 Berger VLD Hunting and 168 Nosler ballistic tips all seemed to give .75 to 1 MOA plus flyers like you reported. I used mostly 41.2 grains as that charge shot great in a FN 308 SPR, lengths were 2.775 to 2.8".

I find the factory trigger to be real long in travel and very rough and attribute that to the flyers I seem to get also. That along with the semi auto action rocking the boat both seem to affect accuracy.

Have you had a trigger job done? Just curious if it made any improvement.

 

[westcliffe01]

Always take a second weapon of a known performance level to the range and start out shooting that. That will tell you if you are "in the zone"... Then shoot the "new" weapon. 3 groups with a new weapon is not much. Have heard that the triggers were not good.

 

[thatguyshm]

What's the round count on the weapon? I know with any at AR I build, I wait for about a hundred rounds or so to make sure everything has settled down. The only one I didn't was a DPMS 338 fed that just shots lights out right from the start. It was awesome.

 

[300WineMag]

I am probably right around 150 - 200 shots fired but haven't kept track. That barrel is chrome lined and supposed to be good for 10,000 rounds so I figured just keep shooting. Good point though, even the trigger itself will probably smooth out some with more shots fired.

I think a trigger job would do wonders, love the gun but the trigger is one of my least favorite.

 

[thatguyshm]

I have a Bill Springfield trigger on my 6.8 and it is amazing. Very crisp. Always a thought. It will smooth out tho, no worries.

 

[USGILT]

If the flyer always comes on the 3rd or 4th shot of a five shot group, I would look at bench technique, rather than a problem with the rifle.

You could also close up the bullet to lands distance and see what happens.

+1 for 168 gr and 175 gr. mine likes both 168 AMAX and 175 SMK.

42.8 to 43.0 of Varget with the 168 Amax is the sweet spot on my rifle.

Always work up your load and reduce your charge by 10% if using MIL brass.

Load:

42gr. Varget
168gr Hornady AMAX
CCI 200
OAL 2.800

 

[alaska]

The military switched to IMR 4064 in the M118LR load by Federal

41.7 of IMR 4064
175 Sierra MK
Fed 210 GM
FC Match brass or
M118LR brass
Suggest a very light crimp with Lee Factory Crimp Die

The Military canceled the use of Reloader 15 due excessive pressure variations
At the time ATK owned both Alliant Powder and Federal Cartridge Company.
Federal has used IMR 4064 in their Gold Medal Match load for years.
That is why military switched to IMR 4064 very stable powder at different temps.

 

[benchracer]

After going to the range, I took 3 5shot groups was not so happy....every 5 shots I had 2 fliers. 3 shots were about 3/4 moa. its 9Degress F out this morning with a 3mph L to R wind. I used all steps to make brass and loads ALL the same. some of the LC brass is from diff years only thing I have not checked is case weight. im wondering if its me shooting? or the imr 4064 in cold weather, or seating (2.797) or scope (vortex 1x5) dang im going nuts now and my brain wont stop turning. 44gr seems to be the correct load(powder) any help or wisdom would be awesome!!

set up:
scar 17 (308)
Lake city brass
cci primers
imr 4064(44gr)
168gr hornady hpbt

Using single stage press, rcbs AR dies with crimp.

In a magazine fed, self-loading rifle, such as yours, it is not uncommon to see two distinct groups form as rounds are fed from alternate sides of a double column magazine. I have experienced this myself.

As a first step, I would recommend that you shoot some 168 grain match ammo through your SCAR to establish its baseline behavior with ammo of known quality. That will give you a basis for comparison with your handloads, along with an idea of the potential available in your rifle. You may also wish to test match ammo with other bullet weights, such as 175 or 155, to see if your rifle shows a distinct preference for a certain bullet weight.

Try shooting some groups by turning the gas off and single feeding your rounds by hand (without using the magazine). If the fliers go away, that will tell you the issue is not ammo related. You may be able to tune your groups to a limited extent by playing with your gas settings.

Most likely, though, you are going to find that your accuracy limitations will be defined by the inherent mechanical limitations of a magazine fed, self-loading rifle.

 

[alaska]

My Varget load

Varget @ 46.0
CCI-br2 primers
168 Sierra MK
WW brass

A very good combination with Varget
Again light crimp using Lee Factory Crimp Die

45.0 with 175 Sierra MK

 

[USGILT]

Make sure your barrel tension screws are all torqued to 62 in/lbs.

If not pull your barrel and re-torque to 62 in/lbs in sequence as denoted in the operators manual.