the glittery brick (aka 308 win) for tactical matches

[ds1]

first off if anyone wants this topic moved to ballistics - no problem. I have posted it here as it is particular to tactical matches, or rather some issues that deserve a look.....not really related to CSR or belly benchrest though.

 

This year I have been shooting 338 LM but next year I want to try 308 in a 16" tube in my DTA.........there are some major tactical comps here that are limited to 223, 308, 300WM and 338LM (in fact you can shoot what you want but only get to take the dust collectors home if you use one of those cals....supposedly anyway . I want to see if lighter recoil and faster follow up shots help or not also.

 

So baseline Sako TRG 22, shooting Sako 168grn Match (Sierra -smk) gets about 2700fps / 820 m/s. Drop is based on a 0.5cm click scope @ 100m and wind at 2 m/s.

 

200m D = 12.2 clicks W = 3.4cm

300m D = 29.8 clicks W = 8.2cm

400m D = 50.4 clicks W = 15.2cm

500m D = 75.5 clicks W = 25.7cm

600m D = 104 clicks W = 38.9 cm

 

Very few stages at matches are ever past 600m and many much closer but not all are known distance. So how do you best this with a 16" tube in terms of windage and drop..........I guess you don`t but there are options. Looking at mid weight pills a waste of time from initial playing on QL. The 2 extremes 155 grn Scenars (and Bergers - not a good supply here) offer something as do the 208 grn Hornady A max. In fact starting at 2200 fps QL predicts the 208 A Max pills are still supersonic at 1KM......but if I want to do that I have a much better tool for the job.

 

The data below is QL generated based on what I am using and happy with - as always whats safe in my gun may not be in yours. Powder is Lovex SO60, COAL is 2.9"

 

What I expected would be the best compromise of wind and drop was the 155 grn Scenar (bc .508) 44grns Lovex SO60 gets 780m/s (2558 fps) in the 16" tube.

 

200m D = 14.2 clicks W = 3.6cm

300m D = 33.5 clicks W = 8.1cm

400m D = 56.8 clicks W = 15.5cm

500m D = 84.2 clicks W = 25.7cm

600m D = 114.6 clicks W = 38.2 cm

 

So it sucks. Same windage and more drop....just a shorter tube.

 

How about the 208 grn A max (bc .660) gets 672 m/s (2200 fps) with 40 grns of Lovex SO60

 

200m D = 18.9 clicks W = 2.2cm

300m D = 44.2 clicks W = 5.9cm

400m D = 73.3 clicks W = 11.6cm

500m D = 105 clicks W = 18.8cm

600m D = 139 clicks W = 27.3 cm

 

Windage wise it rocks .....has the 600m drift that the other two get at 500m....a 11cm improvement can easily make a difference between a hit and miss and 4cm at 400m is quite an advantage with no sighters trying to break clays.

 

Drop....like a lead balloon about 30 more clicks at 500m (0.75m more drop) but actual difference say between 400m and 500m values is more bearable.....roughly 25 clicks 155 / 168 compared to 30 clicks 208 so a potential difference of 12.5cm at 500m.

 

It is still easier to get the elevation right rather than the windage so the 208 A max is looking favorite at the moment. One year later I might know if the elevation is screwing things up or not or if much of the difference is getting lost in the noise of temperature change etc.

 

So has anyone else got any better glittery bricks, if so please share....to be used at tactical comps they need to be mag length, accurate and give some preferably unfair advantage over everyone else.

 

 

[tackb]

What about the 185 otm?

[ds1]

whats the bc on the otm please?

[Scotch_egg]

I look forward to to this one David. I had always aired on the side of fast and flat with a 155gr .30 bullet. I have recently gone back to 175gr SMK's though because of better accuracy though my rife.

[ds1]

True Dave, accuracy is most important. I just feel that with a short barrel I should at least try to get on a level playing field.......before I used 168 grn smk`s in it....easy accuracy but I kept it for 300m comps. The 185 otm`s might well suit though.....nice big jump from 175 .460 bc ( in general) to .560 185 grain bc`s. The 208 A max seem a bit difficult accuracy wise but go ok through the 1:8 DTA tube, not so good through my AI 24" though.

 

The bc of the Berger 185 otm`s looks like 0.560 G1.......calculated I could stuff 41 grains of SO60 in for 708 m/s (2322 fps).

 

300m drop = 40.1 clicks W = 7.1cm

600m drop = 130.7 clicks W = 32.7cm

 

So a few less clicks for elevartion and a bit more windage........sort of splits the difference between the 208 A max and the others.

 

I also noticed the otm 230 grain has an insane bc...0.719 but too long me thinks for 308.

[TC]

185 OTM and RL17 is a combo worth looking at Dave although it's dirty and some claim temp sensitive. I had good results from a 20" 1:10

 

Ballistic tipped match kings improve BC over the standard and should be worth modeling.

 

Run some QL models with barrel length increases looking at % powder burn to understand the trade offs if you are restricted on powder choice. It's worth modelling slightly faster powder too looking at burn and efficiency.

 

Have fun !

 

Tony

[Deserttech Europe]

I have a customer getting over 2700 using wildbore and a 155 grain bullet. I have not checked pressures or anything but he is extremely happy in accuracy ES and SD.

 

I personally use the 175 SMK because I know it well and it is accurate in my barrel.

 

Ewen

[dannywayoflife]

I get 2350fps using ramshot big game and the 208 amax. I also get 2720 using wildbore and a 155 grain bullet. Both through my 16" covert accuracy is stunning

[Deserttech Europe]

Thanks for jumping in Danny..

 

Ewen

[dannywayoflife]

Honestly when I got the 16" barrel I thought It was too short. But now having owned it for a while and have 600 rounds through it I can honestly say when I've burnt this 16" barrel out I'll replace it with another factory lowther dta tube.

[ds1]

Danny, having shot both the 155 and 208 grain pills which one do you prefer?.....Do you notice any difference in wind drift?

[dannywayoflife]

I love them both to be honest. I use the 155's for 100-800 and the 208's for 800-1200.

[terryh]

Dave,

 

The main displacer of the 308 was the windage thing, estimating range for the odd UKD is down the worry list as opposed to estimating windage on every shot - remember no dialling physically possible a lot of the time in some comps so it is a driver on rifle set up. Someone turned up with a 243 running DTAC's (think it was George Gardener?) and everyone went 'wow' - couple of years later it was all 'windcheaters' - does not help you much, but points to the area to concentrate on.

 

'The' 308 load at the time (about 10 years ago) was 175g SMK's and it was interesting that when CorBon chose a bullet fo a 308 only comp, this was the bullet of choice.

 

Can you get hold of the RS powders - they seem to be doing good things re. velocity gains?

 

T

[dannywayoflife]

Terry I was looking at making the change to RS52 as everyone says you get more speed but are you going to get much more than 2720fps from a 16" barrel?

 

DS1 I'd say for out to 800 find a load using the 155 scenar looking to get 2700 with good accuracy. Then shoot that, the 155 scenar has a very good BC and you can drive it a lot faster than the 175's

[terryh]

Terry I was looking at making the change to RS52 as everyone says you get more speed but are you going to get much more than 2720fps from a 16" barrel?

Danny,

 

probably not - that is pretty fast for the short barrel, I was just throwing in the RS as it seems to be the flavour of the month and another make that Dave, due to his location, might find easier to get reliably, no aother reason?

 

T

[ds1]

Danny and Terry, I think the first up will be the 208 A max. Drop, I can map my rifle every 25m out to 800m (real world) so I can live with the rainbow trajectory. If not the 155 Scenars are the next stop......as I can get a regular supply unlike the Berger 185 otm`s.

 

I want to see how good the 208 A`s are though. I can seat them at 2.9" in the mag and at that they are also just touching the lands. If all goes well it might be worth looking at a few Davy modified mags for a longer COAL with a long throated, longer barrel say 24" 1:9. Idea being to stuff as much powder in the case by seating the bullet above the neck shoulder junction (gets rid of potential donut problems too).

 

At the moment with 338 I have around the same bc with 250 Grain Scenars but 2900 fps.....it is flatish and does well in the wind. The 208 A`s would give me the same bc with less velocity. After playing with it in 16" I should have an idea if I want to start messing about with mags and a new tube.

[dannywayoflife]

Davy modded my mag for extra col and he did a fantastic job I've got to say

[joepineapples]

Hi all.

First post here I think

Friend has a DTA and tried his 16" barrel for first time the other day. Great results from 100 to 1000+ yards with Berger 175g otm tac's and 46.5g cfe 223. Can't remember speed ( he's out grafting at moment and his memory is as good as mine) but was about 2500ish

[ds1]

Thought that I would give an update on this thread - 208 grain A max boolets - I decided to test these in a precision comp - most targets cca 1/2 moa from 100 - 500m. (I like to give stuff a fair test and not base anything off the odd group or two). In short I was fooked, the 208 A max can group well but produced flyers also. I put these flyers down to me but nothing seemed strange - NPA, cheek weld, trigger etc. I would say over the 60 or so rounds in the comp it was grouping or capable of shooting to 1 MOA

 

So next up 155 grain Scenars at a plod comp. Even during initial testing things ere obviously different - at 75m (max testing range that I had available at the time) every 5 shot group was 1 hole......not even trying. So plod comp - about the same set-up small 1/2 moa targets out to 300m with some stress induced - target id, time etc. It was a completely different experience to the A max - the Scenars were shooting easily sub 1/2 moa based on about 60 shots and the result was good.

 

The only other thing that I changed was the bipod from a Atlas to a Harris but otherwise everything other than the boolet was the same - same rifle, scope, cases, case prep, same powder (different charge wt), primers- but accuracy changed dramatically. If anything in theory the 208 should have suited the rifle twist rate of 1:8 better than the 155 Scenar.........for now I can live with the 155 grain Scenars - accurate, available and cost 1/2 the price of the A max.

 

The load (use at your own risk - it was safe in my rifle, yours may be very different). Sako brass, CCI BR primer, 43.5 grains of Lovex SO60, 155 grain Scenar, COAL 2.84". Velocity 809 m/s @ 10c temp in a 16" barrel).

[Lukas_K]

308 is more than capable (accuracy-wise) for all competitions shot in CZ/SK. One thing to note up front and consider well: there are no UKD targets. We´re shooting at regulated ranges. After few visits, you have all the ranges (including the odd military ones, scarcely open for public comps like Doupov or Bzenec) learned enough that even if the match director wouldn´t tell, you´ll still estimate the distance pretty accurately. And I don´t even remember having to do that in all those past years...

 

Once you´re comfortable with that bit of practical reality - which means that you´ll always have your drop - it all boils down to two things, (1) windage and (2) recoil.

 

Windage is not much of a problem at the given distances (90% matches up to 375m), with modern bullets and reasonable loads, the difference barely starts to show up. Plus it´s a warm feeling to you knock-off that 6BR with a standard military cartridge But it´s all being shot often pretty fast. Besides Olomouc and Holesov, where the timing remains at approximately 1 shot / 1 minute, all other comps became much faster paced to add difficulty. In Poříčany, that means shooting 30 rounds in 15 minutes - over 3 distances and total of 8 different targets. If you get tired of the recoil by those last few shots... that´s where the flyers are earned.

 

We´ve moved from 308 to 6.5x55 this year, for exactly that reason. Recoil reduction is significant, and better ballistics just put the icing on the cake.

[ds1]

Lukas, nothing new about 6.5x55 in CZ. Lastuvka was using it about 15 years ago at Libava and Strelna and did well recently in Slovakia with it and I did well with it at Strelna at 1KM and later with 260 Rem at Libava. The only comps that I shoot in now are plod ones at Holesov (not skp) and the international at Libava and P. Mareks comps at Strelna and Bzenec. For Libava and Bezenec 338LM works for me as plod comps are restricted to military calibres . At Holesov plod comps are restricted to 308 only. If you do skp at Holesov or Jaslo on sheltered 300m ranges only then you need 6br in open class. I notice that for this year's military comp at Bzenec the military calibres only restrictions has been dropped.

 

In short sometimes the rules state only 308 and if not I prefer 338 for less wind error and still keep the military calibres restrictions.

[Lukas_K]

Agreed, military (or "service") calibres are more do-it-all from that perspective, as you can shoot in any comp without being moved to the special/open category by the rules.

 

I´d also add reloading to my original post, too; thinking in volume, "service" calibres are cheaper as one can always get once fired brass easily. One cannot discard that, when the specials like 6BR have to be bought new off the shelf. Just between my better half and myself, we´ve burnt in excess of 3K rounds last year in precision rifle comps. Haven´t shot much this season (moving house and associated stuff), but looking for the upcoming matches already!

 

But to get back to your original topic - try 155grs Scenar/44grs D073.5/S&B primer/SAKO case and play with OAL. This load worked exceptionally well in a surprising assortment of rifles (my old 26" RPA, several 24" Tikkas, 20" remmy700). I was getting velocities just shy of 900m/s from the 26" Bartlein. Another node was at 42grs (860m/s), and I got pressure signs between 45-46grs (915-920m/s).

[ds1]

Thanks Lukas for the load data.

 

For non service do-it-all round I would be looking at 6x47 Lapua with Swiss powder and 105 bergers.

 

Comps....early December out to 1km at Strelna. Belly benchrest not tactical. Organiser P. Marek. Ideal for 6.5x55