too much varget out a 20" bbl?

[anthonylapoint]

Hey guys, I had a quick question that I have been thinking about. First, specifics: I have a R700 SPS, which is a 1-12 20" barrel and I shoot Sierra 155 Palma's at 300 yard matches (maybe 600 next month).

Im loading 44 grains of varget and developing a 43.5 load, this is a mild load.

If I want to develop a load of say...46 grains of varget, will the blast be exiting the barrel and destabilizing my bullet? Is 46 grains enough powder to be to much for a 20" barrel and extra powder will not benefit my round? Is it true that you want to match the amount of powder with the lenght of the barrel?

Any advise would be nice to hear. Thanks

Tony

 

[roggom]

Re: too much varget out a 20" bbl?

46 was the high accuracy node for my SPS-T 1:12 20" bbl shooting 155 scenars. Sure you may see a little flash if shooting in a dark indoor range, but in order to take advantage of the higher BC of that round one must obtain a higher velocity. The scenar and maybe the palma should be clocking 2900 fps to achieve the optimum BC, but I do not think it is possible from a 20" tube (at least seated to mag length).

For me, I shoot and hunt, so looking at the ballistic tables, the trajectory may simulate a 178 or 180 gr bullet, but the energy downrange is not what I wanted. So I stuck with 178's

Folks with a 24 or 26" 1:11.2 tube should be able to throw the 155's like a champ.


To answer you original question, the amount of powder ( or your accuracy node) , depends on the type of shooting you do. If you will only be ringing steel at 300, then no reason to hit the high node. The most important thing is to look at your drop table and see when your load goes transonic. If it is past 600 then you are good to go with what you are shooting now.

After 2 years of workups 155's 168's 175/178's I narrowed it down to 178's for an all around one load one bullet recipe. They will take me to 1000Y and I dont have to worry about performance at any range up to that point.

 

[Ol' RD]

Re: too much varget out a 20" bbl?

To answer your other question, No. Unless your barrel has a damaged crown the gases will not destabilize the bullet.

 

[poke5353]

Re: too much varget out a 20" bbl?

I am running a 22" barrel but I am using AR-Comp with the 155 Palmas and I am getting about 2925fps and it is about 10mils out to 1100 or so. I am getting great groups when I am doing my job.

 

[anthonylapoint]

Re: too much varget out a 20" bbl?

roggom, what velocity were you getting out your 20" using 46 grains with the 155's? Are you using 46 with with your 178's now? Hows the accuraccy?

Thanks everybody for your help and suggetsions

 

[MitchAlsup]

Re: too much varget out a 20" bbl?

As a note: I use 47.8 gr Varget behind 155 Scenars in a 24" tube getting 2925-2950 fps. {47.4 gr Varget in Lapua cases.}

It is true that you want to match the powder (plus case+bullet+primer) to the harmonics of the gun. It is not true that my load would be too much in a 20" tube, you just have to start low, and work your way up.

 

[roggom]

Re: too much varget out a 20" bbl?

For this load

155 Lapua Scenar
RP, WLR
2.825
46 Varget

I was getting a mean of 2810 at 4850 elevation, they were good groups at 100Y about 3/4-1" and I remember they were comfortable to shoot as well.

Now I have virtually one load, one for steel one for critters.

178 HNDY Match
RP WLR
2.828
44.5 Varget

178 Amax
Lapua WLR
2.830
44.5 Varget

Accuracy is sub-moa for sure at 100Y, not gonna lie and say it is one hole, but i get an occasional cloverleaf. Palm size groups at 600 with a flyer here and there.

 

[chavezz556]

Re: too much varget out a 20" bbl?

Now I have virtually one load, one for steel one for critters.

178 HNDY Match
RP WLR
2.828
44.5 Varget

178 Amax
Lapua WLR
2.830

So I take it the 178 match round is for steel and the amax is for critters ?

How well does the 178 amax work on say a nice cow elk ?

 

[USW.260]

Re: too much varget out a 20" bbl?

Just coming here to ask the same question. I've done load work for 24" barrels but now that I picked up a 20" Tikka T3 Tactical I'm gonna need to work some new loads. I just hate thinking that I'm throwing unburned powder out the end of my barrel.
Anyways I'm thinking about trying the faster burning powders like 3031 or something like that until it just doesn't work then back to Varget!

 

[anthonylapoint]

Re: too much varget out a 20" bbl?

Roggom, youre right about slow 155's, what is the point of shooting them if im not takng advantage of the bc with high velocity.In my 1-12 twist, I just figured that a 155 would be the most accurate. Since im shooting within 600 yards, im going for accuracy over velocity. 168's would probably shoot just as accurate in that barrel twist and would work better then 155's on animals. Also, cheaper and easier to find.

 

[roggom]

Re: too much varget out a 20" bbl?

If you keep em under 600 a 168 NOScc or HNDY match over 44.8 or 45.5 of varget will shine out of your SPS-T

 

[anthonylapoint]

Re: too much varget out a 20" bbl?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: roggom</div><div class="ubbcode-body">If you keep em under 600 a 168 NOScc or HNDY match over 44.8 or 45.5 of varget will shine out of your SPS-T </div></div>



Thanks Roggom, ill give that a try when my box of 155 depleats.