AnthonyR Posted October 10, 2011 Report Share Posted October 10, 2011 Just putting the final details together for the spec of a 20 Tac I am having built on a Sako 75 action. I was thinking of a 20" barrel but I am concerned about weather I will get enough velocity with the 39gr SBK or the 40gr V-Max has anybody got real world experience of a 20 Tac with a shortish barrel. I would like to get to 3500 fps without punishing the brass and rifle too much. I have found a set of Redding Competition dies but don't know where to start with the neck bushing sizes because as yet I have no rounds to measure, I am planning on using the Lapua/Dakota brass with a light neck turn. Powder choice, plenty to choose from here but I am currently thinking of using N133 unless somebody has a better choice Link to comment Share on other sites More sharing options...
Wsm Posted October 10, 2011 Report Share Posted October 10, 2011 You won't have a problem getting 3500 with a 20" barrel Mines 21" and around 3900 without any real pressure signs Link to comment Share on other sites More sharing options...
AnthonyR Posted October 10, 2011 Author Report Share Posted October 10, 2011 You won't have a problem getting 3500 with a 20" barrel Mines 21" and around 3900 without any real pressure signs Which bullet and load are you using to get that? Quickload gives 3352 fps from a max load of N133 in a 20" barrel with 40gr V-Max Link to comment Share on other sites More sharing options...
Wsm Posted October 10, 2011 Report Share Posted October 10, 2011 Which bullet and load are you using to get that? Quickload gives 3352 fps from a max load of N133 in a 20" barrel with 40gr V-Max To be honest a mate of mine loads for me so I don't have any info other than its 39 Blitzkings & N133.The only thing I can say is to take Quickload with a pinch of salt as you'll be surprised with the real time results I'm also experimenting with a 20" BR which is knocking on for 4000 Speak to Dasherman as he built both mine and has run both calibre's as well Link to comment Share on other sites More sharing options...
Scotch_egg Posted October 10, 2011 Report Share Posted October 10, 2011 I was getting 4000fps with the 39gr Blitz King over a hefty charge of RL10x with amazing accuracy. It has however given the primer pockets a punishing. I am now shooting N133 charge weight of 25.7gr achieving 3900fps with no issues. I haven't been able to attain the same level of accuracy as the RL10x. All out of a 20" Pac Nor. Link to comment Share on other sites More sharing options...
Wsm Posted October 10, 2011 Report Share Posted October 10, 2011 Which bullet and load are you using to get that? Quickload gives 3352 fps from a max load of N133 in a 20" barrel with 40gr V-Max Thinking about it are you certain all the values are correct on your Quickload input ? 3350 seems an awfully long way from 3800-3900 Link to comment Share on other sites More sharing options...
AnthonyR Posted October 10, 2011 Author Report Share Posted October 10, 2011 Thinking about it are you certain all the values are correct on your Quickload input ? 3350 seems an awfully long way from 3800-3900 It is quite possible I have made a mistake but I can't see where at the moment. Using 20 Tactical (20-223) as a base gives a max pressure of 55,000psi which is reached using 23.2 grains of N133 with a 20" barrel and Hornady 40gr V-Max. You lot seem to be using a lot more powder than that, most of the loads on the 6mmBR website are also over that. Link to comment Share on other sites More sharing options...
gunnery Posted October 10, 2011 Report Share Posted October 10, 2011 Hi Antony i use 23grns N133 40grn v-max and Dakota brass MV 3550 out of a 1-9 twist pac-nor 26" barrel superb accuracy another one of dashermans rifles. you can drive them harder but i find 3550 plenty with extreme accuracy Link to comment Share on other sites More sharing options...
Alycidon Posted October 11, 2011 Report Share Posted October 11, 2011 Run the ballistic charts, look at the drop/drift differences between 3300 and 3500, minimal, under 250 yards where most of your shots should be then practically nothing. To get those speeds (3500) comfortably from Tac 20 you should be looking at 32-33 gr bullets, driven hard they will go over 4000 but I am a firm believer in downloading hence 32-33s. I drive 39s at about 3600 in my 20BR, again that is downloaded for accuracy and ultra smooth shooting, I could drive them at 4000 probably but at a high cost in barrel and case life. All my rifles run in the 3300-3600 corridor, all on the same zero, nothing has ever moved when hit centre chest. Personally I see no point in running a hot hot load with muzzel flip and short barrel and case life for the sake of another inch or two correction on a scope. I see we have another 20BR convert !!, now that is where it is. Awsome caliber IMHO. A Link to comment Share on other sites More sharing options...
jordang Posted October 11, 2011 Report Share Posted October 11, 2011 I used to run 23gr N133 and 40 vmax for about 3500. Nice and mild to shoot and plenty accurate. I had no need to beef it up. Link to comment Share on other sites More sharing options...
Guest Scotland_Rifles Posted October 11, 2011 Report Share Posted October 11, 2011 im getting 3560 with a Dasherman custom built 20" rifle in 20 tac and thats with a 39gr pill. bob. Link to comment Share on other sites More sharing options...
AnthonyR Posted October 11, 2011 Author Report Share Posted October 11, 2011 Thanks for the info so far, very useful. Anybody got an idea which size neck bushing to go for, just want to get one for now so I have somewhere to start from. Link to comment Share on other sites More sharing options...
22/250 foxer Posted October 11, 2011 Report Share Posted October 11, 2011 I was getting 4000fps with the 39gr Blitz King over a hefty charge of RL10x with amazing accuracy. It has however given the primer pockets a punishing. I am now shooting N133 charge weight of 25.7gr achieving 3900fps with no issues. I haven't been able to attain the same level of accuracy as the RL10x. All out of a 20" Pac Nor. nice one good to see someone pushing those little 39's to the limit. flat out is allways good Link to comment Share on other sites More sharing options...
TonyH Posted October 11, 2011 Report Share Posted October 11, 2011 I can see that a 20" barrel might make it slightly easier to clamber in and out of vehicles, or crawl through undergrowth, but IMO it restricts unduly the velocity potential. I don't go for maximum MV at all times, since accuracy is foremost, but I'd have thought the potential of 20Tac for accuracy combined with high MV was one of its attractions - assuming the prime purpose is varmint hunting. My rifle is on the short side - 22" PacNor on a Win Featherweight, done by Dasherman - but it gives me 3850fps using the Nosler BT40 on top of 23.7gr of N130, without excessive pressure at all. Shortening the barrel still further seems counter productive - and muzzle blast would be exacerbated considerably (I don't use moderators, always wear electronic muffs, but even so...) I'd happily try N133 but I'm not sure where the dividing line is for bullet weight v powder burning rate, in this chambering. I certainly find N130 very efficient and accurate with these light 39/40gr bullets. Tony ps Anthony, I couldn't get the .229 bushing I wanted at the time for my Redding "S" neck die, but I find the .228 works fine, not excessively tight necks, good consistency/accuracy. This is with Lapua/Dakota brass, and my chamber is SAAMI not tight neck. Link to comment Share on other sites More sharing options...
AnthonyR Posted October 11, 2011 Author Report Share Posted October 11, 2011 I can see that a 20" barrel might make it slightly easier to clamber in and out of vehicles, or crawl through undergrowth, but IMO it restricts unduly the velocity potential. I don't go for maximum MV at all times, since accuracy is foremost, but I'd have thought the potential of 20Tac for accuracy combined with high MV was one of its attractions - assuming the prime purpose is varmint hunting. My rifle is on the short side - 22" PacNor on a Win Featherweight, done by Dasherman - but it gives me 3850fps using the Nosler BT40 on top of 23.7gr of N130, without excessive pressure at all. Shortening the barrel still further seems counter productive - and muzzle blast would be exacerbated considerably (I don't use moderators, always wear electronic muffs, but even so...) I'd happily try N133 but I'm not sure where the dividing line is for bullet weight v powder burning rate, in this chambering. I certainly find N130 very efficient and accurate with these light 39/40gr bullets. Tony ps Anthony, I couldn't get the .229 bushing I wanted at the time for my Redding "S" neck die, but I find the .228 works fine, not excessively tight necks, good consistency/accuracy. This is with Lapua/Dakota brass, and my chamber is SAAMI not tight neck. Thanks Tony, still haven't made my mind up about the barrel length, may yet go for 22". Accuracy is more important than ultimate muzzle velocity, this rifle will be mostly used with an NV sight so 250-300 will be max, I have long barreled 22-250 for longer distance work I will order a .228 bushing and go from there. Cheers Link to comment Share on other sites More sharing options...
Raifuru Posted June 6, 2012 Report Share Posted June 6, 2012 Thanks Tony, still haven't made my mind up about the barrel length, may yet go for 22". Accuracy is more important than ultimate muzzle velocity, this rifle will be mostly used with an NV sight so 250-300 will be max, I have long barreled 22-250 for longer distance work I will order a .228 bushing and go from there. Cheers Old post, but working a load up on my 20TAC now. When using QL for most of my guns, I get pressure signs before I reach the max on QL. Especially on 17 Rem and 270 WSM. However, my 20 TAC will handle far higher pressure (or assumed pressure based on QL output) My max for 10X shown in QL with the H20 correction made is 23.3 grains. I have run this at 25 grains with no problems but found that 24.6 grains gives me best accuracy. I have had 7 loads from the first batch of Dakota brass and the primer pockets are still tight. Using VV130 I found the same issue that went way beyong the QL max. If I turn my brass to 70% I use a .229 bushing with Wilson dies, if I use brass out of the bag without turning I find the .230 bushing is best. Working on the new Nosler 32 Grain bullets I have cracked 4220 with 10x at 25.7 grains. Coconuts at 400 yards are very impressive. I would not suggest using any of the loads I have used as safe in any other rifle. This is just what I have found in my Sako 75. Link to comment Share on other sites More sharing options...
gun nut Posted June 6, 2012 Report Share Posted June 6, 2012 23grains Reloader 7, remy 7.5 primer,Dakota brass, doing 3620fps out of a Lilja 1;11 barrel and shot a .189 group last Saturday while trying out an new mod from One less Charlie (review and pics in new mods forum) Cases go about 9 to 11 reloads before primer pockets are US.This rifle has now fired in excess of 3000rnds and still averages sub.3 groups with 40 vmax and 32 vmax. Mike Link to comment Share on other sites More sharing options...
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