I built an AR-10 in .308 and am looking for the pills she likes best. I have an 18” 1:9.75 barrel, and everything I’ve been reading has said 175 or 178. I don’t reload yet, and probably won’t for a while. My question for the hive mind is this: Is there a company out there that will let me do a “mix and match” thing where I could grab 5 rounds of this ammo and 5 of that and 5 of that so I’m not having to buy $20 worth of shit that I may not shoot more than a few rounds of?
- Thread starter OlieTheDog
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BHW stainless match if I remember correctly
Car
BHW stainless match if I remember correctly
You are not going to be able to tell much with 5 rounds. A 20 round box of ammo is a just a fair start.
If you try some BH 175 SMK or FGMM 175 it will likely preform to near your rifle's peak accuracy. It is also likely unless you have shot a large semi auto AR platform quite a bit you will be the weak link in the chain.
This... and IMHO between each brand of ammo, you really need to "season" the barrels bore to the next round.
5rds will do it... then shoot for precision.
I have seen this "phenomenon" enough ( with 10rd groups ) to believe in the season your bore to the next tested round.
It is worth the money spent.
yeah not 5 rounds, but wholesalehunter and grabagun both have low or fixed rate shipping, so if you buy a box of each different ammo, you don't get super screwed on shipping by not buying in case qty's. but start with federal gold medal 175g and you may not need to try a bunch more.
I'm sure the 175 SMK will work quite well. I think I have a box or half a box of 175 Federal Gold match if you'd like it, just pay for shipping and it's yours I don't own any ,308 rifle or honestly know anybody who does anymore.
I agree with @bigjake83 and @rth1800 , generally. First observation is that you have a very tightly wound barrel for .308, but not too far off 'standard.' We usually see 1:10 to 1:12, and 4-6 grooves. So, with a fast rotation, go with longer pill. Personally, I like 175gr, and pretty much shoot and recommend Federal and Black Hills. I am not a reloader, and their match ammo is super-consistent.
I 1000% accept this. With this being my first "accurate" semi-auto system, I know I'll have a lot to learn. That said, I'm trying to limit the amount of mistakes I make. Especially since my wallet can only take so much abuse hahaha.
So you're saying that if I start out with, say, FGMM and shoot a group of them, then switch to BH 175's, I'll have to shoot a number of rounds with the BH's before starting to group with it? Why is that?
Sending PM now
I can't explain it... I have fired enough 10rd groups routinely, to notice a trend in groups tightening up ( from the first shoots, then settling in for the last shoots. ) when changing ammo brands .
So basically my 10rd groups would slowly tighten up, then settle in for the last 5 rds.
I will say, not every factory round would do it.. but there certainly was enough of a trend to distinctly notice it.
There used to be a CMP list of what powders not to fire after one another... IE when using a different load /powder for inside 300yds, followed by a 600yd different / powder load.
So as far as I can tell... it has to do with the powder.
And again, I have no scientific proof.. but just have noticed it from the various factory load testing I have done.
I usually will spend all day doing those "factory" load tests.... so that has also helped make it "easier" to see.
Next barrel I test for precision with factory rounds ( a 6.5CM Kreiger ) , I am going to note the order of firing, and record that info.
Very scientific! I think that’s what draws me to this. There are so many little nuances that can effect how you develop your loads/pick your ammo/etc. I guess I’ll be buying some boxes next go around. Thinking the 175 FGMM is the way to go
YMMV....Be sure to try the 168gr FGMM as well.. and one of the best 10rd S/A .308 groups I have fired was with 155gr Horn. AG ( FN CHF CL 20" PSA upper, my usual tricks )
I actually shoot AG through my 6.5cm bolt gun. That stuff can outshoot me right now, so it’s not making a whole lot of sense to pay more. Just shot my first PRS match and was making 1 moa shots out to 6–700 without much difficulty.
get a couple of boxes and use the first one to "settle" the barrel. it should tighten up once it's been shot a few times.
So not really a textbook “break in” but still a break in?
The term for what is being described is “Barrel Memory”. I don’t claim to be any kind of expert on the matter but apparently it was first observed in large caliber weapons (read artillery). The best I can explain in layman’s terms is this:
After shooting a particular type of round when swapping to a different kind of round the accuracy degrades a bit for a few rounds then returns to what one would expect of the new round.
Just a guess but maybe it has something to do with the way the various barrel deposits line up for a particular type of round. As the new rounds are fired things get rearranged and fall into a new equilibrium.
Maybe someone else can explain this in detail but that’s all I have read on the matter.
Each powder leaves a distinct residue, when you change propellants it takes a few rounds to season barrel as you'll get a different chemical reaction.
Same / similar thing happens with jacket material. How the jacket material in barrel interacts with a different jacket material influences how the barrel / ammo behaves until you reach a "stable" point.
Personally, I try to not mix but that isn't always practical or possible. Depends on your accuracy wants / needs.
Same / similar thing happens with jacket material. How the jacket material in barrel interacts with a different jacket material influences how the barrel / ammo behaves until you reach a "stable" point.
Personally, I try to not mix but that isn't always practical or possible. Depends on your accuracy wants / needs.
Fgmm is very consistant ammo in our 308 bolt gun.
Every time I clean a gun it takes at least 5 rounds to get it to settle down.
If you are breaking it in that can drive you batshit crazy if you expect consistancy,
There will not be any yet. Dont pay too much attention to groups or poi till you get it broke in.
Also leave the crono at home for a while it will speed up with break in.
Have been breaking in a 6.5g this week, shots 15-20 of 10 round sets between cleaning
Started to tighten up nicely but poi shifted again, that is normal for me.
After cleaning this time I expect my first 5 to be trash, and the poi to change slightly less
than last time on the next 5.
After break in settles I usualy get 2 cold clean bore slop shots at a minumum.
I have a 22lr that takes about 20 shots to get running right after cleaning and more if changing ammo.
Relax and lower your expectations during break in so you don't have an anurisom. Lol
Imho
Every time I clean a gun it takes at least 5 rounds to get it to settle down.
If you are breaking it in that can drive you batshit crazy if you expect consistancy,
There will not be any yet. Dont pay too much attention to groups or poi till you get it broke in.
Also leave the crono at home for a while it will speed up with break in.
Have been breaking in a 6.5g this week, shots 15-20 of 10 round sets between cleaning
Started to tighten up nicely but poi shifted again, that is normal for me.
After cleaning this time I expect my first 5 to be trash, and the poi to change slightly less
than last time on the next 5.
After break in settles I usualy get 2 cold clean bore slop shots at a minumum.
I have a 22lr that takes about 20 shots to get running right after cleaning and more if changing ammo.
Relax and lower your expectations during break in so you don't have an anurisom. Lol
Imho
55 meters to 600 yards mostly for cost we have been using the 150 grain federal American eagle we have been getting it around 14.99 for 20 or 374.75 for 500 . but have pondered trying the 500 round I saw of 7.62x51 149 grain from lake city just to try it for 239+ 16.70 for shipping or the Winchester version of the federal is just a little cheaper , since federal seems to have lowered there price on there page to 15.99 maybe that will lower some of the other places as well , I do not know . I went and got a bunch of 168 grain smk and while its nice to shoot , at the cost paid I will not just use it as plinking ammo think it was 21something per box of 20 or something like that .
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Spent a little time in the test shed at Quantico Range 1 back in 91 between Va Regional and Interservice. Ran M14s thru the test bench at 300 yds. When we switched from M852 to M118 Special Ball he said "First round will go to 10 o'clock about a minute out" sure enough, 1st round was right where predicted and following 5 shots were all about 2-3" to the 4 o'clock from the first, right on top of the M852 paster from previous group. He didn't explain the why. He just said that's what happens and you need to accommodate it when switching ammo.
FWIW... if you do buy a variety of ammo to try, and end up with a bunch of 1/2 full boxes.. just save them for the next rifle in that caliber.
And don't forget to try some of the Mil-Surplus... I have seen quite a few perform very well for the price.
This is 20rds of the Sanitized MEN / DAG with the groove cut around the case head face ( German Surplus Import laws.. ) ...
AND don't buy a crap load if you aren't comfortable with that milled out groove... I haven't had any issues... BUT all my 308 AR's are setup with Heavy buffers, recoil springs, and an Adj.GB... and those parts make extraction occur at a lower chamber pressure
This was from a OEM PSA ? DC Machine SS 18" barrel... 20rds , 100yds, scoped, benched, bagged front and rear squeeze... rapid fire.. shoot get back on target, shoot... and this was after a ton of other various factory rounds fired that day.
And don't forget to try some of the Mil-Surplus... I have seen quite a few perform very well for the price.
This is 20rds of the Sanitized MEN / DAG with the groove cut around the case head face ( German Surplus Import laws.. ) ...
AND don't buy a crap load if you aren't comfortable with that milled out groove... I haven't had any issues... BUT all my 308 AR's are setup with Heavy buffers, recoil springs, and an Adj.GB... and those parts make extraction occur at a lower chamber pressure
This was from a OEM PSA ? DC Machine SS 18" barrel... 20rds , 100yds, scoped, benched, bagged front and rear squeeze... rapid fire.. shoot get back on target, shoot... and this was after a ton of other various factory rounds fired that day.
