270 win, low V

[NWBlacktail]

So I finally took my 270 win out and shot it over my chrono (you may remember I shot my chrono last time, so this is a new one). But I was a bit disappointed with the velocity. But it's grouping great! And it's fundamentally a hunting rifle, although it's the rifle I like to tinker with the most.

Rem 700 BDL, 24" factory barrel, 270 win
Timney trigger (3lbs), B&C Medalist stock.
Win brass
140 grn Nos AccuBond
58.0 grns H4831sc
WLR primers

50 deg F, sunny with no wind.
10 round test string
AVG velocity: 2806 fps
Standard D: 6.5 fps

Best 3 shot group was all three touching. 5 shots groups have the first 3 touching, but the 4th and 5th start to spread. Still 5 shot groups are under 1 MOA.

So what's to complain about? It doesn't get much better then that for a hunting rifle. But several load manuals would have that load around 2950 or so??? Is it worth changing anything for another 100 or so fps? :?:

 

[hubcap]

Some rifles just don,t deliver the goods with H-4831. I do not get the best velocity in my rifles either with H-4831. Try a little IMR-4831 with the 140 AB. 2950 should be a piece of cake. Your 24 inch barrel should get you there without any worry. IMR-4831 is faster burning than H and surely gets the speed I want. Accuracy has never suffered with the IMR version for me.

 

[Sas874runner]

Have you worked past the 58 grs. I worked mine all the way to 62.0 gr at which point I started to see primers flatten. My previous load was 59 gr shooting sub moa. But I also found a group that I believe could be easily tweaked to pull in a flier. 2 in one hole and a third about an inch out. That was at 61.5gr. My load at 59 gr was 2924 with a 140 ab. And dang near the same rifle. Rem 700 adl 24" tube.

 

[DrMike]

Your case volume may be sufficiently different from the test case to account for the difference. Primer lots can vary significantly. Though people doubt it, lot-to-lot variation in burn rates can vary by 5% or more. All these factors have an effect on velocity. Is the barrel length in your rifle identical to the test barrel? If the velocity needs to be boosted, you can built in 0.5 grain increments to increases velocity, watching for overt pressure signs. Chances are good that you will match what is listed in the guide. You may even find that accuracy is improved as velocity increases.

 

[hubcap]

Have you worked past the 58 grs. I worked mine all the way to 62.0 gr at which point I started to see primers flatten. My previous load was 59 gr shooting sub moa. But I also found a group that I believe could be easily tweaked to pull in a flier. 2 in one hole and a third about an inch out. That was at 61.5gr. My load at 59 gr was 2924 with a 140 ab. And dang near the same rifle. Rem 700 adl 24" tube.

Man, I only get 2880 with 60 gr. from my 22 inch barrel. Dr Mikes points are well taken regarding lot to lot differences. I may have chrony checked a cold lot of H-4831. When powder becomes available again I think I will re-shoot 59 to 60 and see what happens. Your load with 59 gr. of H-4831 is very close what I get with 56 gr. of IMR-4831.

 

[Sas874runner]

At 62gr I was @3092. But again pressure signs started to show so I stopped there. I do like the fact that h4831sc is an extreme powder. I am still wery of high temps and shooting high loads. But I will check it when summer rolls back around to be safe.

 

[NYDAN]

NWBlacktail,

I had the same velocity problem with my .270 Win (Rem 700 Custom with 24" barrel) and H4831sc. I was only getting around 2800 fps at 59 gr.

I believe there is a lot of truth to DrMike's comments about case capacity and lot to lot variations. My case capacity is at 71 gr. which may be a contributing factor in my case. Also, the lot to lot variation may be a factor. We may have gotten "cold" lots of H4831.

On the advise of others on this forum I tried some RL22 and achieved velocitys of 2921 fps at 56.5 gr. with WLR primers and Norma brass. My extreme spread was only 6 fps. In the spring I am going back to this load and play with the seating depth.

Based on other's comments on this forum, I also want to try some IMR 4831.

Good luck working it out. I am very interested in your results so please post with your progress.

 

[FOTIS]

Try RL 22 or H4350. Sometimes they respond to a faster powder.

 

[NWBlacktail]

Thanks guys, I have some RL22. I'll play with it, have till next fall to get it ready for hunting again, so plenty of time to tinker.

I don't have IMR 4831 or any 4350, maybe I can see what shows up on the on the shelves in the coming months.

 

[SJB358]

I will 2nd the good Doctor's advice, most factory rifles seem to have a chamber a little bigger than what the books are using for testing. Incrementally creeping upwards is safe and like he also said, you might find another spot that shoots just as well, with more velocity.

Different lots and primers will affect it quite alot as well, but I see larger chambers being the culprit quite a bit now that I measure case capacities and judge them against what QL is using. This has been very true amongst the 270, 30-06's, 7mm Rem Mags, and 300 Win Mag's..

 

[hubcap]

I will 2nd the good Doctor's advice, most factory rifles seem to have a chamber a little bigger than what the books are using for testing. Incrementally creeping upwards is safe and like he also said, you might find another spot that shoots just as well, with more velocity.

Different lots and primers will affect it quite alot as well, but I see larger chambers being the culprit quite a bit now that I measure case capacities and judge them against what QL is using. This has been very true amongst the 270, 30-06's, 7mm Rem Mags, and 300 Win Mag's..

Exacty Scotty. I have two .270,s. They are completely different. One is long throated with a larger chamber than the other. The one with with the shorter throat and tighter chamber does give higher velocity. The long throated rifle I use a lot of bullet jump which also lowers velocity as compared to loading close to the lands. There ya go. The rifles presents yet another set of variables.

 

[NWBlacktail]

That is something my Rem 700 definitely has. A huge amount of freebore. I seat the 140 grn AB as far out as I can leaving 0.277" inside the neck, and I still have a good 0.120" (or something like that) to the lands.

 

[kraky]

The "combustion chamber" is more than just the brass casing. Freebore and hanging the bullet out of the casing alot means the bullet is further down/into the barrel as Max pressure is reached. ALL the empty room behind it becomes part of the equation.

 

[EOD Diver]

I've been there too buddy. I was stuffing enough IMR 7828 through my old beater pre-64 270 Win to be pushing the 140 ABs at about 3K (according to the manuals) and getting great groups from 100 to 760 yds. With it I killed several elk handily. You can bet I was surprised when when we put a chrono to the load and it was kicking out a little under 2800 FPS! Also, I'd almost be ashamed to tell you the velocity my Nosler Legacy in 300 Win is kicking out 200gr ABs, but it's so accurate that I'm afraid to even touch the seating die or charge weight for fear of knocking the stars out of alignment. Only with the promise of the 190 ABLR do I dare mess with anything in that rifle. Anyway, upon finding out about my underachieving velocity I just let it go because I had found accuracy, and in the case of the 270, none of the elk seemed to mind....

Joe

 

[Ridgerunner665]

My wifes 270 gets 2,850 fps with 130 grain BT...that's with 54 grains of H4350.

Hers is a 22" barrel...Remington barrels just ain't cut for the best velocity.

 

[gerry]

My wifes 270 gets 2,850 fps with 130 grain BT...that's with 54 grains of H4350.

Hers is a 22" barrel...Remington barrels just ain't cut for the best velocity.

I was wondering what your speed was, that sounds like a good load for my wife to shoot once we finally get the 270 Win here for her to try.

 

[Ridgerunner665]

My wifes 270 gets 2,850 fps with 130 grain BT...that's with 54 grains of H4350.

Hers is a 22" barrel...Remington barrels just ain't cut for the best velocity.

I was wondering what your speed was, that sounds like a good load for my wife to shoot once we finally get the 270 Win here for her to try.

Its a good load...not much recoil and sub MOA accurate in her rifle.

I went with H4350 to reduce the recoil as much as possible without sacrificing any more velocity than necessary...smaller powder charge than with the slower powders, yet still gives decent velocity.

 

[Ridgerunner665]

One thing though...54 grains of H4350 is a pretty warm load.

Be sure to work up to it...

 

[gerry]

Thanks, will do. H 4350 is one of my favorites and is fantastic in my 260 Rem.