Short barrel .308 and magnum primers?

[ColWhitecakes]

I have a 20" barrel Savage 10FPC that I have used in two F-tr mid-range events. The first go around, I was shooting 190gr SMKs with 41grains of Varget. Although this combination performed very well, I decided to go with a different powder and load combination. Yesterday, I shot 168gr Amax with 42gr of AR comp. I worked this load up because I wanted to try a lighter bullet, and I already had a supply of AR Comp that I use in me and my son's .223s for mid-range. The load is accurate enough from what little testing I was able to do before hand. I shot several .4 MOA size groups shooting out of the bed of my truck (the grass on our personal range is too tall for prone off the ground right now) at 300, which I consider very admirable in those conditions. However, this load produces what I would say was a considerable amount of smoke (not black powder-like, but very noticable), and realising that smoke is the unburnt product of combustion, I know I'm not near getting what I could out of this powder, besides just having a short barrel.
So, what I'm wondering is if magnum primers may help to squeeze a little more performance or efficiency out of this load by perhaps getting the powder charge ignited more fully? Any merit to this thought, or is there any other suggestions out there?
Also, I've looked around the site for info too, but, anyone have any pet loads for their shorter barreled .308s?

 

[Johnboy]

I cannot say anything for the powder of your choice.so I will say this for a start.if your load of 42gn is a light load then try it,I see no harm.now on the other hand if its a hot load then I'll say for you to start over again by 10% working up to your load that you already have.

for the most part the mag primers have just a little more pop ( fire/flash ) and that the cup is a little thicker.so again if its a light charge then go for it.if not then work your way back up to your load.

 

[jo191145]

Might not help you in this circumstance but I played with slower burn rate ball powders in a 30BR.
As expected I was'nt getting full burn. Easiest way to tell is pull the bolt and look down the bore.
If your seeing powder kernels in the bore like I was thats not good.

Tried magnum primers. Actually seemed to make matters worse.
Switched to the mildest primer I know. Wolf SRM. That helped significantly in the unburnt residue matter.
Adding even more powder helped even more.

My wild quess would be the slower ignition actually helped the powder fully burn before the bullet left the bore.
I'd bet cold weather would've thrown the whole expieriment into a funk.

No real help, just a, who woulda thunk it.

 

[ColWhitecakes]

I cannot say anything for the powder of your choice.so I will say this for a start.if your load of 42gn is a light load then try it,I see no harm.now on the other hand if its a hot load then I'll say for you to start over again by 10% working up to your load that you already have.

for the most part the mag primers have just a little more pop ( fire/flash ) and that the cup is a little thicker.so again if its a light charge then go for it.if not then work your way back up to your load.

Although Alliant's published data for the 168gr Amax list the max load as 41.7gr of AR Comp, the 42grs I am loading shows no signs of over-pressure. I had very little time to work a load properly before the match, so I loaded five rounds at 41.7, 42, and 42.3 and shot groups at 300 while checking for any warning signs. Although one would normally work up from a lower starting point, I wasn't too concerned with problems, as I am loading out near the lands and there was abundant case capacity left with all three loads. Ironically, there was no discernible difference in group size or elevation, so I went with the middle load. I am planning to refine this load with a ladder test soon, so as you stated that the magnum primers have more "fire/flash", do you think they might do as I inquired and lead to more complete combustion?

 

[ColWhitecakes]

Might not help you in this circumstance but I played with slower burn rate ball powders in a 30BR.
As expected I was'nt getting full burn. Easiest way to tell is pull the bolt and look down the bore.
If your seeing powder kernels in the bore like I was thats not good.

Tried magnum primers. Actually seemed to make matters worse.
Switched to the mildest primer I know. Wolf SRM. That helped significantly in the unburnt residue matter.
Adding even more powder helped even more.

My wild quess would be the slower ignition actually helped the powder fully burn before the bullet left the bore.
I'd bet cold weather would've thrown the whole expieriment into a funk.

No real help, just a, who woulda thunk it.

Interesting. I think I'll go have a look at that right now. BTW, how were you seated, i.e, jammed, mag length, etc.

 

[necchi]

http://forum.accurateshooter.com/index.php?topic=3790583.0

Where do you merit the idea/knowledge of un-burnt combustion equals noticable smoke?
Have you considered environmental conditions?
Humidity, Dew Point, Temps, Wind?
I'm just wondering where you base this idea,,

 

[jo191145]

135gn SMK's jammed with X-Terminator.

FWIW I would'nt doubt that combo could'nt be made to work.
This particular Frankenstein 30BR has never shot anything well enough to be competitive.
Just expieriments, no vouching for accuracy. It'd make a good dear gun tho

 

[jo191145]

necchi does have a good point.
Not all smokless powders are created equal.
AR comp is a ball powder isn't it?
Ball powders like to run full house in my expierience.


Reminds me of using H-355 in a 6BR 14 twist 21" barrel.
GREAT BALLS OF FIRE. Pretty darn accurate tho.
If I did'nt do all my load development through a range muffler I might have continued testing. Its worked well for others
The sheer flamethrower effect would've unnerved some of my competitors.
I decided I liked myself with eyebrows tho.

 

[xdeano]

honestly a mag primer might be compairable to adding 1 grain of powder. Not much of an addition. If you want to to get down range with more velocity go with a lighter bullet and more powder. I'm shooting a Gap crusader at 22" with a 155g Lapua and 45.4g of Varget and a Federal 210Match primer. You should be in that 2825-2850fps range. Using lapua brass and seating 2.800" With Lapua's decent BC, you'll be far better off then messing with a primer.

xdeano

work up the load as always.

 

[ColWhitecakes]

http://forum.accurateshooter.com/index.php?topic=3790583.0

Where do you merit the idea/knowledge of un-burnt combustion equals noticable smoke?
Have you considered environmental conditions?
Humidity, Dew Point, Temps, Wind?
I'm just wondering where you base this idea,,

perhaps it may not apply as equally to cartridge loads, but smoke is in fact the product of inefficient or incomplete combustion. I base this on a lifetime of observation, as well as over 181/2yrs as a professional firefighter and study of fire science. I did consider the enviromental factors; however, it occurred on both a blistering hot and dry day of load testing and a cooler and extremely humid day at the range (a thunderstorm moved in directly after the match). Though it is a different caliber completely, and all the varibles associated with that, I have never noticed it in my Model 12 26in barrel .223 or my son's 24" barrel .223. Also, I have seen the included post on the federal primers, and others, and the mentioned "throwing sparks further" is one of the reasons I figured in on the possibility of getting my powder charge ignited more fully/quickly.

necchi does have a good point.
Not all smokless powders are created equal.
AR comp is a ball powder isn't it?
Ball powders like to run full house in my expierience.


Reminds me of using H-355 in a 6BR 14 twist 21" barrel.
GREAT BALLS OF FIRE. Pretty darn accurate tho.
If I did'nt do all my load development through a range muffler I might have continued testing. Its worked well for others
The sheer flamethrower effect would've unnerved some of my competitors.
I decided I liked myself with eyebrows tho.

AR Comp is an extruded powder. Seems to be similar to Varget in granule size. I choose it upon advice from a tech at Alliant when I had messaged regarding Reloader 17 for my application. I have also noticed varying amounts of flash and smoke from other powders, but this one seems particular smokey.

honestly a mag primer might be compairable to adding 1 grain of powder. Not much of an addition. If you want to to get down range with more velocity go with a lighter bullet and more powder. I'm shooting a Gap crusader at 22" with a 155g Lapua and 45.4g of Varget and a Federal 210Match primer. You should be in that 2825-2850fps range. Using lapua brass and seating 2.800" With Lapua's decent BC, you'll be far better off then messing with a primer.

xdeano

work up the load as always.

I'm not necessarily looking for just more velocity in general, or rather, at the sake of all else. My current combo is based largely on budget and simplicity. I had a supply of the bullets and powder on hand, and if I can get it to work well, I would like to use the AR Comp, as it is working well in my .223s, and I like the idea of having my components "consolidated" if possible. I have to load for both me and my son and it is easier and cheaper for me to use compatiable components as much as possible. The 190 SMKs shot well and I'm not overly sensitive to recoil; but, as my rig weighs 11 1/2 lbs, including the 1 kilo Millet, the slightly reduced recoil of the 168 Amax is nicer to shoot, and according to the ballistic data charts, offers a better trajectory at the velocities I can push them.

 

[ColWhitecakes]

Another point I failed to make about the lack of horizontal spread with the previously mentioned loads of 41.7, 42, and 42.3 was that instead of this just happening to be on a node or such, I figured that there was a possibility that the additional powder was simply burning outside the barrel and not adding any to the velocity to cause a rise in impact. Of course, this would be easy enough to compare if I had a chrono, but alas.... Thus the interest in getting more from the load through the possibility of getting it to burn more efficiently.