Hey Guys, I recently bought some 130 grain Sierra SPBT bullets which I intend to use in my Ruger 77 MKII rifle. The problem is that my Ruger does better with plain base bullets of 130 grain weight in my Ruger, but not as well with the boat-tailled bullets of 130 grains. I wanted to the plain based bullets but they were unavailable so I bought boat-tailled bullets. I am using 53.5 grains of IMR-4350, but have some H4350 powder which I haven't used yet. Wondering if the H4350 would be more accurate or if there is another powder I could use. At this point the Ruger will shoot only factory or "plain based" 130 grainers in a tight group @100 yards loaded with IMR-4350 powder. Any suggestions, as to which powder would work using the 130 gr. SPBT's, would be appreciated.

David
If you have an accurate load using flat base bullets and the boat tails don't shoot as well with the exact same load try changing the seating depth to see if you notice any change.
If you go closer to the lands make sure that they still cycle through the magazine with the added length.
I'm not a 270 guy but I thought IMR 4831 was the powder of choice for .270's and 130 grain bullets.
H4831 and Reloader 22 show up frequently as accurate loads in .270's as well

Try H-4831 it's a great powder in the .270. I've been using 130 Gr. Hornady flat based bullets with this powder for years. Works great on deer.

quote:

Originally posted by DRS:
Hey Guys, I recently bought some 130 grain Sierra SPBT bullets which I intend to use in my Ruger 77 MKII rifle. The problem is that my Ruger does better with plain base bullets of 130 grain weight in my Ruger, but not as well with the boat-tailled bullets of 130 grains. I wanted to the plain based bullets but they were unavailable so I bought boat-tailled bullets. I am using 53.5 grains of IMR-4350, but have some H4350 powder which I haven't used yet. Wondering if the H4350 would be more accurate or if there is another powder I could use. At this point the Ruger will shoot only factory or "plain based" 130 grainers in a tight group @100 yards loaded with IMR-4350 powder. Any suggestions, as to which powder would work using the 130 gr. SPBT's, would be appreciated.

DRS, my experience with my .270 Win is that the flatbase bullets do give better groupings, but the boat tail bullets could match the groupings if they are reduce a few points of a grain on the load. I also agree with Snellstrom that a change to the seating depth could also make a difference. Usually the boat tail bullets have less bearing survace to the lands and that cause lower pressure, but also a reduction of "matching" with the barrel. By redusing the load you compensate for the reduction in bearing survace.

DRS, in my .270 those Sierra's group like a shot gun. Pie plate size groups at 100 yards. If you switch to NBT's and H4831, you problems will probably go away, assuming your barrel is free floated.

I shot Sierra boat tails for years, working up loads with them and then switching to Speer Grand Slams. The load I settled on was 59 grains of IMR 4831 and a CCI-200, seated .010" off the lands. I later went to 60 grains of AA 3100. Both loads shot cloverleafs at 100 out of my BDL with the Sierras as well as the Speer GS...

My .270 load for 130 grn SGK's is 59 grns 0f H4831SC

My Sako shoots both NBT's and SMK's sub 1/2moa with H4831 both bullets have the same poi as well. I think all you have to do is start working your load from scratch and you will find your sweet spot.

Thanks Guys, all for your good advise. I certainly appreciate it greatly. This is the first time I tried Boat-tailed 130 grainers in my Ruger. I will check the seating depth & reduced loads to see if this will solve the issue. What I am using now, in terms of powder, is the same amount I use for plain base bullets: 53.5 GRS / IMR-4350 / 130 grain SPT. My Ruger is glassbedded to the point there is no pressure on the action or barrel, and also has a Timney Trigger. It is very accurate with Winchester Factory loads & the plain based bullets. Yesterday, after shooting at a 100 Yard target, my groups with the boat-tails were around 1.6" @ 100 yards while the Factory loads grouped < 1" on average. I then places a plastic quart Milk bottle 150 yards away and hit it dead center about 1.5" high with the factory Winchester ammo, but the reloaded 130 gr. Boat-tail 130 gr ammo was asbout 1.5" to the right of the "POA" and 1.7" low. Anyway with all the great advise here; I should solve this issue in short time. I have an old S&W model "B" .308 rifle that shoots Boat-tailed loaded ammo better than plain based bullets. ~Go Figure.