.556 mm IVI
- Thread starter Sequoia
- Start date
5.56mm SS109 (62gr) milspec ammo has a MV of ~3,100fps which is a bit of a challenge to safely reproduce (i.e. stay within safe pressures) using powders and components that are typically available for us reloaders. Also keep in mind that milspec brass is thicker and generally has less case capacity and so you should reduce published loads when developing a recipe that's right for your AR. As a start point, try Googling "Sierra AR-15 reload data" and click on the accurateshooter.net pdf to get a good source of loads with various powders and bullet weights.
You will probably be around 2 grains above any published load data you find seeing as that the SAAMI pressure limits are lower than the Nato pressure limits.
H335 will work (very flashy and temperature sensitive) although you may want to try the CFE223 powder as it seems to advertise higher velocities for the same pressure. AA2230 is supposed to be 'the' powder for loading 5.56 but it seems hard/expensive to get at the best of times.
Make sure you have a 5.56 chamber (throat). Use a chronograph when working up the load. Use CCI 450 or CCI 41 primers. Keep an eye on those primers, if you go to high you will be pierce them or be picking them out of your fire control group and maybe your teeth (remember, your primers won't be crimped in place).
Also make sure your bullets are crimped. You don't want the possibility of a set-back bullet ruing your day and rifle.
As an aside, I have found that PPU 55gr ammo seems to match the velocity you would expect to see in M193 rounds (I know, not SS109 or M855) and it does seem like a way hotter load than your typical AE ammo. I don't know if they make a 62gr variety.
H335 will work (very flashy and temperature sensitive) although you may want to try the CFE223 powder as it seems to advertise higher velocities for the same pressure. AA2230 is supposed to be 'the' powder for loading 5.56 but it seems hard/expensive to get at the best of times.
Make sure you have a 5.56 chamber (throat). Use a chronograph when working up the load. Use CCI 450 or CCI 41 primers. Keep an eye on those primers, if you go to high you will be pierce them or be picking them out of your fire control group and maybe your teeth (remember, your primers won't be crimped in place).
Also make sure your bullets are crimped. You don't want the possibility of a set-back bullet ruing your day and rifle.
As an aside, I have found that PPU 55gr ammo seems to match the velocity you would expect to see in M193 rounds (I know, not SS109 or M855) and it does seem like a way hotter load than your typical AE ammo. I don't know if they make a 62gr variety.
One reason I can think of: ACOG BDC and ELCAN BDC.
paperslayer
Regular
- Location
- Chilliwack
Restricted rifle=approved range=known distances. Knowing your come-ups is important too.
The load you are looking for can easily be duplicated with military brass, a 62 fmj and WC735 powder. It sure works for obtaining the M193 velocities with 55 grainers and I am quite sure it would do it for 62 grain bullets as well.
Longshot, I know it is slightly different from batch to batch, but on average how far off do you reckon C77 / M855 ballistics would be from, lets say, the 1-4 SPECTER DR BDC at x4?
Cheers.
But they don't have the steel penetrator
Winner Winner chicken dinner.
The BDC is useless unless you are using the real deal. The SS109 bullet with the tungsten carbide penetrator is physically longer than a comparable 62g fmjbt/wc using an all lead core.
If you use a different bullet, the BDC will be a useless feature.
For everyone else, your paper target won't care. Unless meeting NATO specs is an entrance requirement for the Loyal Order of Mall Ninjas you are striking for, just load for function and accuracy.
Well I've been shooting C77 for quite some time now out of an issue C7 and elcan at a decent level of proficiency. Realistically with the Bdc gate down ,you are looking at landing somewhere within 0-3 moa of where you aimed. Which may not be much of a problem at 100 or 200m but starts to become more of an issue past that. It will vary with different scopes. You can get better accuracy by running an open gate and tuning things to you. A Spector DR might have a better Bdc. Having never used one I can't really say.
