Short barreled .308 group size

[X11]

Hi there all.

This is my first post as I am new to this site and am wondering if any of you guys can help. I have a RPA Woodland Stalker in .308 win with a 16ins barrel and fitted with a Jet Z mod. I am using 155gr Match Kings over a selection of powder weights using Vit N135 and N140, I will probably change the bullets to 150gr at some time but only have access to 155's at the mo. At 100m shooting three shot groups I am getting a group of around 1inch but with 2 touching and one just away making the group an inch and most of the time the second shot is the straggler.

Any ideas or thoughts?

Thanks

[6.5shooter]

Try a change of primer

[jcampbellsmith]

Two thoughts, try some factory ammo, get someone else to try your rifle and your load. It's frustrating and educational when someone shoots your kit better than you can.

 

Have fun.

 

JCS

[TSG]

I shoot 155 SMKs with a fairly slow load of 41gns of N140 out of a 16 inch barrel. This is about the same as yours, about an inch or under depending on me. The moderator seems to make little difference to group size but the heat haze can be awkward. I use this load because it is ballistically matched with a 180 grain expanding load (same powder 39 grains) at 100 metres.

I would try some 10 round groups to check the grouping capacity of the load, possibly without the mod.

[onehole]

If I had a 16 inch 308 then I would be looking to getting 110 to 130 grain heads over a fast powder to work,,,,,,,,,,,,,135 would be good for this?? What are you using the rifle for?? Target,Deer,,plinking,,,,,,,,,varmint?? yeah love my 308 with 110 vmax on bunnies,,,,,,,,,,,,,,,,,,,,,,,,O

[Jagged 77]

Hi there all.

This is my first post as I am new to this site and am wondering if any of you guys can help. I have a RPA Woodland Stalker in .308 win with a 16ins barrel and fitted with a Jet Z mod. I am using 155gr Match Kings over a selection of powder weights using Vit N135 and N140, I will probably change the bullets to 150gr at some time but only have access to 155's at the mo. At 100m shooting three shot groups I am getting a group of around 1inch but with 2 touching and one just away making the group an inch and most of the time the second shot is the straggler.

Any ideas or thoughts?

Thanks

 

Welcome to the site X11.

 

Your woodland stalker I believe has a 1/10 twist and with that short 16" barrel is most likely designed with the heavier bullets in mind. However each barrel is different and there are plenty of 10 twists out there that love 155's. Sometimes a particular bullet can just shoot poorly which could be the case with your current loading. For proper group size analysis however use 5 shot groups.

 

I personally would be looking at shooting something like the 175 SMK with either TR140 / N140 or N150 - a standard load with lots of data which shoots well in 1/10 or 1/12 twists. You'll loose a bit of velocity with a short barrel but the extra weight and BC of the 175 or similar will help.

[mikeroz]

Yes, I just checked RPA's website & the woodland stalker is 1 in 10 twist. Have you thought about emailing RPA on suggestions of bullet weight they know works well in their gun. I'm sure they will have done some product development before it went to market.

Do you know which of the 3 shots is the one which is the flyer? Is it the first shot? Could it be a fouler shot?

It was said above, try 5 shot groups rather than 3 shots. Take careful note of where each shot falls and if there are any flyers if there's a consistent order to which one's a flyer.

How constent is your reloading?

Same case head stamps?

[dannywayoflife]

I'm picking up my dta srs covert soon which has a 16" fast twist barrel. I'm looking to try the very heavy bullets in her as I've read that they loose less velocity than the lighter bullets in a short barrel. Looking to try tr140 ramshot wildbore and some rl17 with bullets ranging from 190-208 grains

[Scotch_egg]

Good call Danny. I would try 175gr SMK for a start.

 

 

 

The 155gr Palma your are currently shooting, are they 2155 or 2156? I found the 2156 much harder to get to shoot over the 2155 which I just threw any old load together.

 

Keep us updated with your progress.

[Finman]

I shoot an 18 inch .308. I use nothing other than 180gn SGKs for it and I'm getting .2-.3 4 shot groups with it. Best so far .12... I have had hits to 500yrds at Mike Dickinson's ranges to rabbit size targets. Good enough for me...

 

Best wishes

 

Finman

[dannywayoflife]

Good call Danny. I would try 175gr SMK for a start.

The 155gr Palma your are currently shooting, are they 2155 or 2156? I found the 2156 much harder to get to shoot over the 2155 which I just threw any old load together.

Keep us updated with your progress.

I'm looking really at the 190 smk and the 208 Amax mate. I'm told the 190 is still very stable in the transonic zone and the 208 Amax just has a stupidly high bc!!

[c18rch]

208 may need a faster twist in such a short barrel.

[Jagged 77]

208 may need a faster twist in such a short barrel.

 

I believe the DTA covert is a 1:8 which will do it just fine. I've shot 208's out of a 1:12 and got them to stabilize with sub MOA accuracy.

[dannywayoflife]

Yep dta is a 1in8 mate a 1in10 should easily stabalise them also.

[c18rch]

Sorry, I meant for the 1in10. 1in10 is optimum but in a short barrel, it may not achieve the velocity.

[Ballistic Hamster]

as 6.5 shooter says try a different primer and repeat what you have done just change primer just a simple test

[rovershooter]

I'm really happy with my RPA Woodland Stalker and the following homeloads:

 

125 grn Nosler BT - any case trimmed to length - N140 49 grains over a CCI primer gives less than 1" at 100m zero.

 

150 grain Nosler soft point OR ballistic tipped head - any trimmed case + 45.3 grains of N140 over a CCI primer = 2 rounds touching and 1 hole about 1cm away. It then drops about 13cm (the width of a hand) at 200m and knuckle to elbow length at 300m. The group size doesn't open out too much though at 2 or 300m.

 

Incidentally both these loads shoot to the same point of impact through the RPA and on a crappy wet windy/gusty day I put three shots of each head weight into a 4cm circle at 100m. That included shooting without waiting for the wind to drop, wiping the PMII lens and managing to retrieve the target afterwards in one piece to add to my shooting record!

 

 

[gbal]

I'm looking really at the 190 smk and the 208 Amax mate. I'm told the 190 is still very stable in the transonic zone and the 208 Amax just has a stupidly high bc!!

I'll be interested to see how this theory works out-though I don't have a barrel so short.Ballistic performance is influenced by both velocity and weight /BC,and stability by twist (and minimal velocities--hence t he transonic 'problem' as velocity drops...

Just for fun,to compete with a 'standard' 6.5x284 142 BC .565 @ 2950,the 308 calibre needs 220g,.627 BC ,@ 2650- which would be a bit of a handful,recoilwise ( or 23+ lb weight,which snookers it for fclass etc).

But your on interesting lines using the heavies-keep us posted!

I'm going to try the other way -110g varminters-if available-but of course,at much shorter ranges....?500 ish?

Gbal

[dannywayoflife]

Will do mate! I'm picking her up soon Ewen the importer tells me that he uses 208 amax's as well

[X11]

Try a change of primer

Ok I will give that a go, I am using Remingtos at the mo but may have some CCI kicking around.

[X11]

Try a change of primer

Ok I will give that a go, I am using Remingtos at the mo but may have some CCI kicking around.

Two thoughts, try some factory ammo, get someone else to try your rifle and your load. It's frustrating and educational when someone shoots your kit better than you can.

 

Have fun.

 

JCS

I have tried some factory Norma with 150 Noslers but they were really bad around 6ins at 100m. My shooting buddy has tried my gun with my loads and gets the same results as me!

[X11]

Try a change of primer

Ok I will give that a go, I am using Remingtos at the mo but may have some CCI kicking around.

Two thoughts, try some factory ammo, get someone else to try your rifle and your load. It's frustrating and educational when someone shoots your kit better than you can.

 

Have fun.

 

JCS

I have tried some factory Norma with 150 Noslers but they were really bad around 6ins at 100m. My shooting buddy has tried my gun with my loads and gets the same results as me!

I shoot 155 SMKs with a fairly slow load of 41gns of N140 out of a 16 inch barrel. This is about the same as yours, about an inch or under depending on me. The moderator seems to make little difference to group size but the heat haze can be awkward. I use this load because it is ballistically matched with a 180 grain expanding load (same powder 39 grains) at 100 metres.

I would try some 10 round groups to check the grouping capacity of the load, possibly without the mod.

Hi mate think it may have been you I spoke to on the phone the other day!

Have tried your loads and they are better, byt am still getting the flyer!

[6.5shooter]

Ok I will give that a go, I am using Remingtos at the mo but may have some CCI kicking around.

 

This advice was given to me by Mike Norris at Brock and norris a few years back when I was having a similar problem.

Mike is a wealth of knowledge when it comes to reloading due to his extensive testing on various rifles that he builds!

If in doubt give him a phone, hes a very nice guy who will tell u straight without any bullsh1t.

[X11]

If I had a 16 inch 308 then I would be looking to getting 110 to 130 grain heads over a fast powder to work,,,,,,,,,,,,,135 would be good for this?? What are you using the rifle for?? Target,Deer,,plinking,,,,,,,,,varmint?? yeah love my 308 with 110 vmax on bunnies,,,,,,,,,,,,,,,,,,,,,,,,O

Yes havnt tried anything lighter then 150 as yet. I will use it for all the above that you mentioned, but I will try some lighter ones.