308 load for BDC scope

[Shiloh]

Good day,

I have a 7.62 4-14x56 Springfield scope on my M1a with the built in BDC and was wondering if anyone may know what the recommended load is to keep the BDC accurate at distance. I just started loading some rounds for the rifle and began zeroing at 100yrds when I noticed the scope was actually set up for a 200yrd zero. I noticed the next tic mark indicated 300yrds on out to 1000 so I re zeroed to 200yrds. I hand loaded some 168gr Horniday Amax w/41gr IMR 4895 traveling about 2550fps and was shooting prone off a backpack while hitting clay pigeons at the 300yrd mrk. I noticed I was doing OK but want to bump the fps up a little to about 2600+ for the longer distance. I'm not sure if the scope is supposed to be calibrated for the 168gr round at a certain fps or the M118 175grn type round. Any clarification would be grateful.

[PrimaryArms]

308 load for BDC scope

http://www.primaryarms.com/v/vspfiles/manuals/PA4-14XFFP308%20Instruction%20Sheet.pdf

All the load data is listed and how to zero it.

[Shiloh]

Nice info. Thank you. The scope is different on the internals but the bullet drop info is helpful. I didn't realize there isn't much drop between 100-200 yards. It started to become pretty substantial by 300.

Once the 30mph crosswinds let up a little here I'll have to try out the info and see what happens.

[PrimaryArms]

30 mph! Lol

[PrimaryArms]

Oh wait you got the ACSS Orion then
Go to picture 21

https://www.primaryarms.com/Primary_Arms_New_4_14X44_Front_Focal_Plane_Scope_p/pa4-14xffp-orion.htm

[JMP]

This is an inherent disadvantage with a BDC reticle. For better accuracy, it's best to get a load that works well in your rifle rather than your BDC.

[Shiloh]

30 mph! Lol

I know it sounds ridiculous bet its true. Between 20-30 mph the last week. It sucks. I watch a screen at work which gives me all of the weather readings and lately the ave seems to be 25mph.

My range runs from South to North and we've been getting the crosswinds from the West. All of our streets run West to East so I get great tail winds going to work and God awful headwinds coming home. Usually first thing in the morning is the best time to shoot like right now but today I have to go to work. I hope its like this tomorrow. =)

[PrimaryArms]

I know it sounds ridiculous bet its true. Between 20-30 mph the last week. It sucks. I watch a screen at work which gives me all of the weather readings and lately the ave seems to be 25mph.



My range runs from South to North and we've been getting the crosswinds from the West. All of our streets run West to East so I get great tail winds going to work and God awful headwinds coming home. Usually first thing in the morning is the best time to shoot like right now but today I have to go to work. I hope its like this tomorrow. =)

Crazy! Just aim about 60ft to the left!

-Dimitri

[Shiloh]

This is an inherent disadvantage with a BDC reticle. For better accuracy, it's best to get a load that works well in your rifle rather than your BDC.

Thats what I figured. Ive been playing with a Remington 700 trying to work up a load with 175gr SMKs using a SWFA 10x mil dot and doing a bunch of research for the 1000yrd shot. I was reading that you can work a load for 100yrds (Easy groups) that may not work so well at distance. The M118 round was supposed to be 42gr IMR 4895 w/ 175gr SMK which I loaded up and my group on paper @ 100yrds was rough compared to a slightly lighter load. I decided to boil down my accuracy to the assumed MOA standard of 1" @100yrds, 2" @ 200, etc. I believe thats the military standard. If I get a dinger report from 1000 Id be happy. Not trying to shoot apples off the top of the target yet though.

[Shiloh]

Crazy! Just aim about 60ft to the left!

-Dimitri

Ha ha, I know right!? I don't even bother trying with all the sand that gets blown around. I guess it would give me extreme variables training though. I should try it sometime just to see what happens. It will certainly be a challenge keeping the barrel steady.

[PrimaryArms]

308 load for BDC scope

Thats what I figured. Ive been playing with a Remington 700 trying to work up a load with 175gr SMKs using a SWFA 10x mil dot and doing a bunch of research for the 1000yrd shot. I was reading that you can work a load for 100yrds (Easy groups) that may not work so well at distance. The M118 round was supposed to be 42gr IMR 4895 w/ 175gr SMK which I loaded up and my group on paper @ 100yrds was rough compared to a slightly lighter load. I decided to boil down my accuracy to the assumed MOA standard of 1" @100yrds, 2" @ 200, etc. I believe thats the military standard. If I get a dinger report from 1000 Id be happy. Not trying to shoot apples off the top of the target yet though.

You can have a load give you a good group at 100 yards but because its got a low BC or is slow in fps not perform as well further out. What JMP is saying is not always true. Your on the right track trying to line up your bdc and get your fps up.

Do you know what the moa or mil measurements on the BDC marks are? What fps are your getting with 175smk?

-Dimitri

[FMJBT]

I used to run the Springfield BDC scope on my Savage 10FP in 308 about 10 years ago. The scope itself is calibrated for 168 Match ammo at around 2700 FPS if I remember correctly. From my experience shooting, or rather trying to shoot 168 BTHP out to 1000 yards with that scope I can tell you that anything beyond about 850 yards is wishful thinking with that BDC. At lower elevations common to coastal areas, the 168 grain bullets go subsonic and begin tumbling well before they get to 1000 yards.

I ended up using some 175 grain surplus M118LR out of that rifle to get consistent results at 1000 yards. What worked best for me was to shoot the rifle at that distance, and then zero the 1000 yard BDC mark with where the bullets were impacting. With the furthest BDC mark set to be dead on, the shorter range marks all lined up very close to there respective ranges. At 100 yards the rifle was shooting just a bit high, around an inch or less as I remember.

[PrimaryArms]

I used to run the Springfield BDC scope on my Savage 10FP in 308 about 10 years ago. The scope itself is calibrated for 168 Match ammo at around 2700 FPS if I remember correctly. From my experience shooting, or rather trying to shoot 168 BTHP out to 1000 yards with that scope I can tell you that anything beyond about 850 yards is wishful thinking with that BDC. At lower elevations common to coastal areas, the 168 grain bullets go subsonic and begin tumbling well before they get to 1000 yards.



I ended up using some 175 grain surplus M118LR out of that rifle to get consistent results at 1000 yards. What worked best for me was to shoot the rifle at that distance, and then zero the 1000 yard BDC mark with where the bullets were impacting. With the furthest BDC mark set to be dead on, the shorter range marks all lined up very close to there respective ranges. At 100 yards the rifle was shooting just a bit high, around an inch or less as I remember.

Yes the 175gr is a much better choice

-Dimitri

[missiondude]

If your BDC scope is an adjustable power second focal plane scope you can match the BDC to the theoretical drop of what ever ammo you happen to be shooting all the way out until it goes sub-sonic. You will usually be less than 1 MOA off using the preset distances of the scope.

[FMJBT]

If your BDC scope is an adjustable power second focal plane scope you can match the BDC to the theoretical drop of what ever ammo you happen to be shooting all the way out until it goes sub-sonic. You will usually be less than 1 MOA off using the preset distances of the scope.

The Springfield scopes were FFP, some of the early pioneers of FFP tactical scopes.