Tikka 308 increase velocity options?

[wildwilderness]

My son has a nice upgraded LH SS Tikka chambered in 308 win with a 20” Proof prefit. We changed the bolt stop and have LA mag but the throat on the barrel won’t allow seating bullets out far. The 178 eldm max col to the lands is about 2.87”.

With the space of the tikka action and mag I would like it to go about 3”- So the options are to have the throat moved- I have seen options to DIY this, or have a smith do it with dummy rounds.

How much velocity do you think will be gained With a longer throat?

the other thought was to just rechamber the proof barrel and was looking at the 30-06 AI... that should clean out the old 308 chamber and still fit in a Tikka action and definitely increase velocity!

we are looking for hunting out to about 600yds for everything in NA.

what do you think? Longer throat good enough or just go ‘06 AI? Will the 20” barrel make the gains less?

 

[rayporter]

if you gain 30 fps i would be surprised. now if it allows you to change powders and get more in the case, who knows.

i have used a throater once and it is tricky. go slow and test often.

 

[False_Cast]

You will not increase the rifle’s effective range by an appreciable measure with a longer throat.

What is your current velocity and what velocity are you looking to achieve? What is your minimum impact velocity with your chosen bullet?

 

[bruceleroy]

As that beautiful rifle sits, that is already a 600 yard capable gun. For reference I am getting 2650 with 178 ELD-X out of an 18" barrel with zero pressure signs. That gives me 1800 fps at well beyond 600 yard/meters with plenty of horsepower behind it to ensure expansion.

 

[CApighunter]

Have you shot it yet? I think it’ll be just fine as is. You could also drop to a lighter bullet to pick up more speed. I’d probably sell the barrel and buy a 30-06 barrel rather than rechamber if you still want more horsepower.

 

[tdot]

I had a 22" barrel re-throated earlier this year, rhe increase was substantial, i requested 0.100" and received 0.150". It was a disappointment. I saw minimal bump in velocity with the same speed powders (25-50fps) and with slower powders that I hadn't reached pressure with previously, I could now reach pressure, but still wasnt seeing the same speeds as the faster powders. I think maybe a longer barrel would have seen better results.

 

[thinhorn_AK]

Nice looking rifle.

 

[wildwilderness]

Hard to get many powders to test with corona shortages. Yes the rifle is acceptable as is, but always nice to have a bit more. Will have to get the velocity numbers.

I really like the shorter barrel for busting through alders.

what are your favorite 308 win hunting Bullets? I like the higher BC to cheat the AK winds

 

[rayporter]

personally i would get a new rifle [or rebarrel that one]

a new chamber will probably do what you wish but that short barrel is not going to help matters.

 

[gbflyer]

There is some pretty impressive load data out there using powerpro 2000mr and ramshot tac with 178-180gr bullets. Usually the test data is gathered with a 24” barrel, however .308 responds well to a shorter barrel. Might be worth a try.

 

[wildwilderness]

Just spoke to the local gunsmith and he happens to have a 30-06 AI reamer... said it wouldn't be much to rechamber, plus the AI would clean up the 308 win chamber...

 

[Wapiti1]

In a 20" barrel, figure 2650-2700 with a 180gr bullet for the 30-06 AI. I can get 2900 in a 24" barrel with RL23. RL19 or similar would be what I would try in the shorter barrel.

For rechambering a .308, I like the 30-284, but that usually goes in a short action.

Just bumping out the throat on the .308, you're only going to gain a two or three grains of case capacity.

Jeremy