Range Report Load on the slow side, What next??

[Pete E]

Using 45grn of Varget, 155 grn Lapau Scenars and CCI LR primers I have put together a load which has decent accuracy (.5 MOA) in my factory spec Howa with a 22" barrel.

Target 3 is 5 shot 5/8"..Target 1 & 2 are around 3 shot 3/8" groups.

However, this is only giving me an average of 2665 fps and I was hoping to get around 2800fps...Also, despite each charge being weighed and the brass being prep'd ect, it has a velcoity spread of about +/- 25fps. SD for 15 shots was 13.6fps

So two questions,

1)Despite the accuracy, should I give up on this combo and try another powder and if so, which one?

2)Regardless of whether I change powder or not, how do I bring down the extreme spread? Maybe change to Fed 210 primers?

Regards,

Peter

 

[Sig685]

Re: Load on the slow side, What next??

If you like the accuracy, why go faster? What is your intended use for this rifle/load combo?

 

[Pete E]

Re: Load on the slow side, What next??

I want to eventually ring steel out to 1000m with it, and after running it through JMB it seems that its approaching the transonic point at around 900m...

For now I'm quite happy to use it, but I'm wondering if I should be looking at a load which gives higher velocities and similar accuracy.

If i stick to Varget, there seems to be another accuracy node at 48.5grns, but bolt lift is a bit sticky by then, although the primers and the case look fine...

 

[Lindy]

Re: Load on the slow side, What next??

Extreme spread - more properly called the range - is a dubious figure of merit.

For why, see:

http://www.shootersjournal.com./Features/Haps/EnglemanChronographStatistics.pdf

I can certainly see why you might want to go a bit higher in velocity, though.

 

[MitchAlsup]

Re: Load on the slow side, What next??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Pete E</div><div class="ubbcode-body">Using 45grn of Varget, 155 grn Lapau Scenars and CCI LR primers I have put together a load which has decent accuracy (.5 MOA) in my factory spec Howa with a 22" barrel.

However, this is only giving me an average of 2665 fps and I was hoping to get around 2800fps...Also, despite each charge being weighed and the brass being prep'd ect, it has a velcoity spread of about +/- 25fps. SD for 15 shots was 13.6fps

So two questions,

1)Despite the accuracy, should I give up on this combo and try another powder and if so, which one?

2)Regardless of whether I change powder or not, how do I bring down the extreme spread? Maybe change to Fed 210 primers?</div></div>

My long range Scenar load follows:
Brass: Winchester
Powder: Varget 47.8 gr
Primer: CCI
Bullet: 155 Scenar
OAL: 2.948"
MV: 2925-2950 fps from 24" barrel

Use caution going up to this level. Watch pressure signs on the way up. Subtract 0.4 gr for Lapua cases.

To bring down the ES and SD you need to do everything consistently. Start measuring powder to 0.03 gr (if you can), seat primers to the same depth (if you can), seat bullets to 0.002" on the ogive (if you can), match prep all your brass, keep the brass in sets; KEEP IMACULATE books on your process and progress. Once you get the ES/SD down, you can relax the consistency standards on one item at a time to find the range overwhich it has minimal effect.

With all that said: it is exceedingly difficult to get an SD under 12 fps (and, of course, ignore ES). If you see in my MV spec, there is a 25 fps ES range.

 

[Pete E]

Re: Load on the slow side, What next??

Thanks Gents,

I did try some loads around 48 grns but the bolt started to get a touch sticky and the groups opened up to 3/4" to 1" range...I might try around 47.5 grns again and play with the seating depth. My current loads were worked up with the bullet just kissing the lands. I also might try a different sound moderator, as a different style/weight mod might produce different barrel harmonics.

Thanks again,

Peter