If moly coating doesn't improve grouping, is it at least not detrimental?

QUOTE;

"OK....replace the bbl......
get it recrowned at least.
get a palma chembered krieger 308 win....
something is not right.

my bone stock armalite ar10t shoots 1/2 moa with a small group of 0.338. berger 175's moly'd by me."
________________________________________________
LOL......this IS a new Krieger barrel.

I just finished paying about $375 for this 18" barrel. I added a flash hider to it and it's now a $450 barrel that ain't getting replaced anytime too soon again. :D This is a Krieger Criterion barrel offered by Fulton. However, the only way I was going to get it at a light weight of 2 1/2 lbs and in black finish was to accept it with chrome lining. Fulton claims their chrome lining suffers "no accuracy loss". I Don't know if they use some sought of special lining process and I can fully believe that, but if there is some sought of accuracy loss due to the chrome lining, I don't think I could blame that for my 1" groups.


I used my borescope a couple of days back to examine the crown, and its as sharp and defined as a razor!

I took the original 10 ton 24" fluted stainless barrel off after about 120 shots which shot about the same. (I had the original easier to hold full sized fixed-stock on it too) Well geees.....maybe I just have to learn how to shoot the rifle. :confused:
 
goodgrouper said:
So you're saying that because the moly bullet is farther down the barrel in time the added space negates the fact that there is 2 grains more powder (the solid) turning into gas? Matter is matter. It can't be negated. It is always there in one state or another.
Click to expand...

not negated, but used in the larger volume to get the same pressure and same velocity......
and where have you ever used an addtional 2 gr to adjust for moly ?

i typically in 223 and 308 use 0.2/.3 to 0.5/.6 .

mike in co
 
VaniB said:
QUOTE;

"OK....replace the bbl......
get it recrowned at least.
get a palma chembered krieger 308 win....
something is not right.

my bone stock armalite ar10t shoots 1/2 moa with a small group of 0.338. berger 175's moly'd by me."
________________________________________________
LOL......this IS a new Krieger barrel.

I just finished paying about $375 for this 18" barrel. I added a flash hider to it and it's now a $450 barrel that ain't getting replaced anytime too soon again. :D This is a Krieger Criterion barrel offered by Fulton. However, the only way I was going to get it at a light weight of 2 1/2 lbs and in black finish was to accept it with chrome lining. Fulton claims their chrome lining suffers "no accuracy loss". I Don't know if they use some sought of special lining process and I can fully believe that, but if there is some sought of accuracy loss due to the chrome lining, I don't think I could blame that for my 1" groups.


I used my borescope a couple of days back to examine the crown, and its as sharp and defined as a razor!

I took the original 10 ton 24" fluted stainless barrel off after about 120 shots which shot about the same. (I had the original easier to hold full sized fixed-stock on it too) Well geees.....maybe I just have to learn how to shoot the rifle. :confused:
Click to expand...

sorry to hear you have been dealing with fulton armory.....
it is the reason why the gun shots like it does....
plain and simple a house of fools.
how many chrome lined target rifle do you have( the ar10 does not count..since it is not a target rifle at this point) ??.
how many benchrest 100/200 yd rifles have chrome lined bores ?
its a tomato stake,

mike in co
 
mike in co said:
not negated, but used in the larger volume to get the same pressure and same velocity......
and where have you ever used an addtional 2 gr to adjust for moly ?

i typically in 223 and 308 use 0.2/.3 to 0.5/.6 .

mike in co
Click to expand...

Correct. It is still there. It can't be erased from the equation and it's results can be measured directly. Pressure curves and peak pressures are well documented with strain gauges and flame temps are recorded by most powder manufacturers. These devices show what's going on.


As J Valentine has pointed out, there are many types of Moly sold under the same name. It has different properties from brand to brand. Your results are not directly comparable to mine unless we are using the same brand. But for my brand of moly, I had to bump up my charge 1 to 2 grains to get the same velocity in a 22-250 AI fast twist, a 22-250 slow twist, a 6.5-.284, a .22-284, and a 220 swift. All loads were chronographed before and after and tested for accuracy.
 
goodgrouper said:
Correct. It is still there. It can't be erased from the equation and it's results can be measured directly. Pressure curves and peak pressures are well documented with strain gauges and flame temps are recorded by most powder manufacturers. These devices show what's going on.


As J Valentine has pointed out, there are many types of Moly sold under the same name. It has different properties from brand to brand. Your results are not directly comparable to mine unless we are using the same brand. But for my brand of moly, I had to bump up my charge 1 to 2 grains to get the same velocity in a 22-250 AI fast twist, a 22-250 slow twist, a 6.5-.284, a .22-284, and a 220 swift. All loads were chronographed before and after and tested for accuracy.
Click to expand...

i have neco lab grade MoS2.

when you change the volume behind the bullet in a time window event, you will not see the same peak pressure with the lower load, when you move back up in powder, the pressure comes back up, but at a later time...remember the bullet moves further quicker. the volume behind the bullet is more. the pressure is the same if the velocity is the same......

did your accuracy with moly occur at the same velocity as the naked bullets ?

i suspect you have moved to a node further up the curve.

mike in co
 
mike in co said:
did your accuracy with moly occur at the same velocity as the naked bullets ?

i suspect you have moved to a node further up the curve.

mike in co
Click to expand...

Yes to your first question.

No to your other. I'll pick one of my guns as an example. My 22-284 shot naked Berger 80 grain bullets best at 3550 fps. This was a medium load. I could go higher without ruining cases but the accuracy deteriorated. When the those bullets were substituted with moly coated Bergers and the load was kept the same, the velocity dropped to 3460 or so and the accuracy was gone. To get back to 3550, I had to increase the powder charge by 1.5 grains. Once this velocity was attained, the accuracy (and expected point of impact) came right back. OK. Only now I was putting another 1.5 grains of powder into the case. In other words, it took more powder to get into the node. This doesn't sound like much, but multiply 1.5 by every shot fired from the gun since and it adds up and it didn't do the throat any favors.

This all goes back to expansion ratios and barrel lengths and such which is good to examine.

The formula is pretty simple. A standard industry constant used for figuring bore volume is .773 as taken from cross section of the muzzle. D=groove diameter of barrel in inches, L= length traveled by the base of the bullet from seat to muzzle in inches, and B=bore volume in cubic inches. B=LxD(squared)x.773. With that, the expansion ratio can be calculated with the formula: R=B+U/U (R=ratio of expansion, B=bore volume in cubic inches, and U=volume of powder chamber in cubic inches).

So we see that the amount of powder changes expansion ratios even in small quantities. Pressures of expanding gases will peak and change at different times depending on the powder being used but amount of gas going down the barrel is the same amount in volume and weight as the powder put in. Were it not so, you could shoot spitwads or cornmeal down a throat for centuries and not see any barrel wear. You could shoot undersized bullets for caliber infinitely and not record any throat damage. But we know that simply isn't the case. Common sense would say that after you fired a few thousand cornmeal loads down the bore, you would see firecracking. The gases are what is causing most of the damage (in this case) and they are directly related to how much solid is turning to gas.
 
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all well and good, but again the volume changes with time....different volume/time with naked as opposed to moly bullet.........

same bullet, same bbl, same velocity, same pressure......


mike in co
 
ohh and i think i'm moving to BN...................


mike in co
 
mike in co said:
sorry to hear you have been dealing with fulton armory.....
it is the reason why the gun shots like it does....
plain and simple a house of fools.
how many chrome lined target rifle do you have( the ar10 does not count..since it is not a target rifle at this point) ??.
how many benchrest 100/200 yd rifles have chrome lined bores ?its a tomato stake,

mike in co
Click to expand...


NONE. But I'm also not looking for the 1's, 2's and 3's like you and I can get with our bolt action rifles and our handloads that are single fed into the bore and onto the lands. (nor am I even seeking 4's and 5's)


While I would never accept a chromed lined Krieger Criterion barrel for competition shooting, I would be surprised if it shoots poor groups to the "tomato stake" degree that you declare.

As to date, I have never experienced consistant 3/4" shooting with my Rock River 20" NM .223 or my 24" fluted 308. Now having also fired this newest barrel with much the same results (now I'm getting the even larger 1" groups), I'm starting to see a pattern and seriously wonder if it is shooting teqnique with AR rifles that is lacking.

If you are ultimately proved right that the 1" groups are as good as this rifle will get due to the chromed Krieger barrel, then I will still be quite satisfied owning a "field accurate" and versitile SHTF weapon that has exibited 100% reliabiity.

Thanks for not holding back and giving me your honest opinion.
 
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Quote:
Originally Posted by mike in co
same bullet, same bbl, same velocity, same pressure......


mike in co

"Yes, but it took more powder to get there!" by gg

YESSSSSSSSSSSSSSSSSSS

nothing changed in the load except for the coating on the bullet. a coating which reduces friction. so why did the naked load with a moly bullet slow down ?.........volume/time behind the bullet! the slippery bullet moves further, quicker....the powder load never hits its peak pressure(of the naked load) because the volume per time behind the moly bullet is always larger. larger volume, lower pressure, less velocity.

so as you pointed out, you add more powder to get to where you were...a given velocity for a given bullet in a given bbl.



mike in co
 
mike in co said:
Quote:
Originally Posted by mike in co
same bullet, same bbl, same velocity, same pressure......


mike in co

"Yes, but it took more powder to get there!" by gg

YESSSSSSSSSSSSSSSSSSS

nothing changed in the load except for the coating on the bullet. a coating which reduces friction. so why did the naked load with a moly bullet slow down ?.........volume/time behind the bullet! the slippery bullet moves further, quicker....the powder load never hits its peak pressure(of the naked load) because the volume per time behind the moly bullet is always larger. larger volume, lower pressure, less velocity.

so as you pointed out, you add more powder to get to where you were...a given velocity for a given bullet in a given bbl.



mike in co
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Agreed, but the point I was trying to make for some time now is that having to use more powder with moly is a check in the CON box not in the PRO box for the argument to use moly. If a shooter can get equal accuracy, equal barrel life, and the desired velocity from moly and bare, why would he want to use more powder to get the same performance? Never mind the bigger mess, the extra steps, the extra cost, the wasted ammo having to lay down more moly after cleaning to get desired POI, and the bigger cleaning mess of moly. The CON boxes are far outnumbering the PRO boxes here. Perhaps that's why benchresters have all but abandoned the stuff.;) I, for one, haven't gone through withdrawals yet over it.
 
goodgrouper said:
Agreed, but the point I was trying to make for some time now is that having to use more powder with moly is a check in the CON box not in the PRO box for the argument to use moly. If a shooter can get equal accuracy, equal barrel life, and the desired velocity from moly and bare, why would he want to use more powder to get the same performance? Never mind the bigger mess, the extra steps, the extra cost, the wasted ammo having to lay down more moly after cleaning to get desired POI, and the bigger cleaning mess of moly. The CON boxes are far outnumbering the PRO boxes here. Perhaps that's why benchresters have all but abandoned the stuff.;) I, for one, haven't gone through withdrawals yet over it.
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lol
yes....go look at the the one and only claim i made about moly....shoot the same longer.

some br shooters spend the extra time on loading, instead of cleaning, or socializing......
in short range br its a toss up of personal choice.

i'm pretty sure i'll be using bn on my 1000yd gun

mike in co
 
mike in co said:
lol
yes....go look at the the one and only claim i made about moly....shoot the same longer.
Click to expand...


I have not even found that claim to be true. I've spent many a day in prairie dog towns with moly and bare bullets and no cleaning and couldn't tell a difference on hit ratios even past 1000 yards. The difference I did see was that when I finally did get around to cleaning was that the bare bullets gave stacks of blue patches and the moly bullets gave stacks of black patches followed by another stack of blue patches!

There have been times in competition, I have had something come up to where I didn't have the time to clean my barrel and had to shoot the entire agg without cleaning. I have won some of those aggs. Would I have won better had I cleaned? I doubt it. I've seen Tony Boyer do the same thing. He doesn't panic if the gun hasn't been cleaned and his relay is called to the line. He just shoots it and often wins it.
 
goodgrouper said:
I have not even found that claim to be true. I've spent many a day in prairie dog towns with moly and bare bullets and no cleaning and couldn't tell a difference on hit ratios even past 1000 yards. The difference I did see was that when I finally did get around to cleaning was that the bare bullets gave stacks of blue patches and the moly bullets gave stacks of black patches followed by another stack of blue patches!

There have been times in competition, I have had something come up to where I didn't have the time to clean my barrel and had to shoot the entire agg without cleaning. I have won some of those aggs. Would I have won better had I cleaned? I doubt it. I've seen Tony Boyer do the same thing. He doesn't panic if the gun hasn't been cleaned and his relay is called to the line. He just shoots it and often wins it.
Click to expand...

So what is the chemical composition of the coating on the bullets you used?
 
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