Rooky Pressure Problems Updated!

BBB

BBB

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Alright, so I started loading for my .270 WSM a couple of weeks ago.
At first, after I got the WSM sizing problems worked out, everything went well.
Worked with H4831sc from the Lyman Manual, 63 gr through 67.5 gr pushing 130 grn Rem cor-locs .020 off the lands.. No pressure signs until 67.5 when the bolt got just a little heavy to lift. Groups at or under an inch at 63 and 67 grains.

Then I tried some reloader 19 and 130 gr TSXs: Very heavy bolt lift showed up at the minimum load (63.5 grains). I pulled the rest.

Same time out, I shot the last of my cor-locs at 63 grains of H 4831 as fouling shots - they went into less than an inch.

Also tried some Speer 130 gr SBTs with the same powder charges as listed in the first paragraph. Heavy bolt lift and bad cratering showed up at 64.5 grns - accidently fired one at 65.5 grains (stupid, I know) - bolt lift was scary heavy.

Went out again today - TSXs over H4831 this time - pressure signs on starting load again - 64.5 grains, Barnes' recommended minimum.

So what's going on? I'm going to load up some more of the SBTs and TSXs tonight, running from 59 - 63 grains. Hopefully those'll work. But I'm surprised that I could push the cor-locs with a heavier powder charge than either of the better quality bullets.
 
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Simple: those "higher quality bullets" are stiffer and oppose more resistance to being pushed in a barrel than Remington's more conventional Core-Lokt which can upset easier.
Perhaps the length of the bearing surface is longer on those two premium bullets and thus friction is greater. More friction equates to greater back pressure so you need less of a given powder to get to the working pressure of the load.
I would be curious to try some moly-treated TSXs just to see where the pressure goes with the same loads. Usually, moly-coated bullets need MORE powder to attain a given working pressure.
PP.
 
The core loks are very soft and will normally not show pressure signs as early as some other bullets.The tsx will usually show pessure signs a couple of grains sooner than most cup and core bullets.
 
BBB said:
Alright, so I started loading for my .270 WSM a couple of weeks ago.
At first, after I got the WSM sizing problems worked out, everything went well.
Worked with H4831sc from the Lyman Manual, 63 gr through 67.5 gr pushing 130 grn Rem cor-locs .020 off the lands.. No pressure signs until 67.5 when the bolt got just a little heavy to lift. Groups at or under an inch at 63 and 67 grains.

Then I tried some reloader 19 and 130 gr TSXs: Very heavy bolt lift showed up at the minimum load (63.5 grains). I pulled the rest.

Same time out, I shot the last of my cor-locs at 63 grains of H 4831 as fouling shots - they went into less than an inch.

Also tried some Speer 130 gr SBTs with the same powder charges as listed in the first paragraph. Heavy bolt lift and bad cratering showed up at 64.5 grns - accidently fired one at 65.5 grains (stupid, I know) - bolt lift was scary heavy.

Went out again today - TSXs over H4831 this time - pressure signs on starting load again - 64.5 grains, Barnes' recommended minimum.

So what's going on? I'm going to load up some more of the SBTs and TSXs tonight, running from 59 - 63 grains. Hopefully those'll work. But I'm surprised that I could push the cor-locs with a heavier powder charge than either of the better quality bullets.
Click to expand...

If you read your reloading manual, I am sure it will state somewhere that the loading data shown is for those components used and if you substitute any component you should reduce the charge and work back up...

Different primers, different makes of brass, different makes of bullets, different makes of powder - any single one can make a change in pressure...
 
The critiques so far are bang on.
If you change any component you have to restart your load development.
That should include powder from a different lot as certain powders are quite reknowned for lot to lot variations, as I recall RL 19 is one of those.
It also states quite clearly in Barnes website that the TSX bullets will usually max. out for pressures sooner than their other offerings.
Consider yourself lucky and learn from this experience.
 
I agree with the above - and after an experience with some really heavy bolt lift and blown primers on a magnum rifle, I became a lot more cautious. Working up every load (and combination of components) from the low end is the only way to go. Another thing I have found is that H4831sc seem to build up pressure faster than the old H4831. Smaller grains I guess.
 
One other thing, is lots of the data in the Lyman manual is fairly old. AS an example it called for at least three more grains with 160 gr bullets in the 7mm mag than any other manual, most manual loads have come down over the years with more sofisticated pressure testing has become available. What happens when you shoot factory ammo inthe gun, any pressure signs, in the 300 WSM I had last year, the only loads that showed pressure were teh Winchester supreme factory loads.
Re the Barnes, they are currently populating a new load manual with some calibres available online to members and most loads are way down, the 270 WSM will most certainly be down. The 300 Win I am loading for at teh moment with H1000 and the load they prev listed as max, you can't even seat a bullet the charge is so compressed, the new load is 3 full grains less.
 
Alright, thanks for the advice everybody. I will point out that I wasn't trying to just switch out the bullets expecting to have a safe load; I was just surprised by the difference in pressure between between bullets and was confirming that this wasn't too unusual.

Went out again today, both Speers and TSXs loaded from 59 to 63 grains of H4831sc. Speer groups started out at 1.5", expanded, then both the 62.5 grn and 63 grn groups did .5 of an inch. Was happy with that, though I think it's too close to max for a practice round, since pressure signs (shiny spot on head and tough extraction) showed up at 64.5 grns, and those 63 grain loads had a little bit of stiffness on the bolt lift.

I'll probably just get more cor-locs and load them up at 63 grains for a nice, fairly mild plinking round.

TSXs - 59 grains did an inch and a half with similar bolt resistance and primer cratering to factory loads, which have always shown some pressure signs in this gun - 60 grains had more pronounced pressure signs and 61 were definitely too hot. For those of you playing at home, 59 grains is almost 8% less than Barnes' recomended starting load.

So one more rookie question - since I don't have a chrony, and don't know what the bullet's doing - should I:

1. Screw around with one more pressure series with the TSXs, probably from 57 to 59 looking for some decent groups.

2. Switch to a slower powder like RL 22 or 7828 or H1000

3.Go down to Wholesale and steal a chrony. Or just go down to the range and hang out and beg somebody to let me shoot one of the 59 grain loads over theirs.

4. Play with seating depth - the TSXs are .050 off the lands - but I was thinking of just seating them to the COL data provided, which would make them .090" off the lands - would that potentially reduce pressure, or would the reduced case volume increase it?
 
BTW I have found that TSX bullet's don't like the .050 jump that the previous barnes bullets needed to be accurate. My best loads with TSX bullets are more like .025 off the lands.
 
So I think I may have sorted it. Went to the range today, with 130 gn Partitions from 58 to 63 grns of H4831sc. Slight pressure signs at 58 grns, too hot at 59.

But, there was somebody there with a chrony who was nice enough to fire a couple of rounds over it for me.

The first, 63 grns of H4831 pushing a Cor loc ran 3127 - faster than the book says, but not bad.

The second round he fired was 59 grains pushing the Partition.

Hornady says this bullet weight with this charge should get 2950 FPS

Speer says it should get 3035

Chronograph said my load got 3267.

So I think I'm likely dealing with a tight bore - that would explain why the harder bullets show pressure signs at min. loads, and why my rifle has always copper fouled so bad.

So I guess I'll just load down to Hornady's minimum load of 55 grains and go up - 58 grains seems to be max, or slightly hotter than max, for the Partitions at least.

Unless anybody else has advice.

I was thinking I should maybe switch to a slower powder too, but I'll see how the new ones do first.
 
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