220 swift imr 4064 low fps

[1984nitro]

So the other day I went out and reworked some loads for my 220 swift. I end up with this load
55gn vmax
remington brass
cci 250m primer
38.0gn 4064
fps: 3640
ES: 43fps (not worried here because very little case prep)
Group: .23"
temp was 50degrees
So my question is isn't this velocity low? According to hodgdon data book 37.5gn gets you 3742. Also do I need to worry about pressure signs come rock chuck season this summer due to the change in temp?
The rifle specs ruger m77 Mark II 24" barrel and 1/14"
Thanks
Eric

 

[SBruce]

My old Ruger 77 Swift shot much tighter groups when I kept the velocity around 3600. Yes, I could get more with 55 grn bullets, but had to FL size and trim cases more often, and accuracy definately dropped when I got above the 3700 mark. I also got way way more rounds through the barrel then alot of guys did before I lost accuracy by keeping the fps down a little.

Mine had a 26" barrel, that extra 2" makes alot of difference in a caliber like the Swift.

 

[Freebore]

I have a custom 27" 1-12 and shoot the 55 Bal-Tips at 3900 using N-160 powder at the top end...that"s what I built it for. I hit pressure before my expected velocity using IMR-4831 but accuracy was very very good. One of the Speer books says N-160 is the powder for the Swift...it was for me. Yea I know everyone swears by IMR-4064. Try a different powder that is a little slower if you want more velocity like IMR-4831. You have to give the rifle what it likes. Yes I have to trim my brass every 2nd firing.
I shoot the Sierra 69's using RL-22 same point of impact amazingly as the 55's to 500 but are much much better beyond 500.

The 220 Swifts are a hoot and just keep the round count down during volleys allowing the barrel to cool. Clean it religiously and you'll get good barrel life. Or you could.....burn it up and get a brand new 26"-27" tube in a 1-12.

Have you tried the 50 bal-tips or the 52's it may just like them better.

 

[1984nitro]

Thanks for the info.
Having the 24" barrel must be the difference in the velocity then.

I have used the 50 v max for a couple year but got tired of sowing up hole in the coyote that came in to close. I went to the 55 for lower velocity and still a good punch. When I get the money I plan to get a 26" custom barrel in a 1-8" to shot the 75 amax for the long dogs in late season.

 

[hypersonic]

So the other day I went out and reworked some loads for my 220 swift. I end up with this load
55gn vmax
remington brass
cci 250m primer
38.0gn 4064
fps: 3640
ES: 43fps (not worried here because very little case prep)
Group: .23"
temp was 50degrees
So my question is isn't this velocity low? According to hodgdon data book 37.5gn gets you 3742. Also do I need to worry about pressure signs come rock chuck season this summer due to the change in temp?
The rifle specs ruger m77 Mark II 24" barrel and 1/14"
Thanks
Eric

I have been shooting 220 swift for a lot of years and the 2 powders I have had the best success with are H-414 and H-4831. It is my favourate coyote cartridge bar none. H-414 is temp sensative when you are working at the upper end so you will have to reduce your load a grain or a grain and one half when the weather is warm. H-4831 is not so problematic with temps but does need more barrel length 26" is better than 24" and although I have not shot a 28" barrel with the swift and H-4831 speed should be better still with H-4831 as it is pretty slow for a case the size of the 220. If you have any give the H-414 a try you might get the speed you are looking for.