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Reload Swiss RS62: Actual V's QL for 6.5 Creedmoor

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As there's not a lot of load data out there for RS powders and 6.5 Creedmoor, I thought it might be helpful to list my own comparisons here:

Barrel:  24 inch;  1/8 twist;

Powder:  RS 62 (single base);

Bullet:  Lapua 139gr Scenar

Brass:  Lapua small primer

Seating at 30 thou off lands for a COL of 2.842"

Muzzle velocities (note actuals are 5 shot averages measured at 2.5m from the muzzle which I know isn't a large sample but it gives an idea).

  Load (gn)          QL prediction                      Actual

41                          2596                                     2372

41.8                       2646                                     2473

42.6                      2696                                      2529

43.6                      2746                                      2608

43.9                      2764                                      2613   

There's a gulf of difference between predicted and actual.  I loaded as far as 43.9 with hardly any pressure signs other than a very very slight squaring off of the primer shoulders.  No case head marks, no stiff bolt, no blown primers.  My own view is that actual results with the T3x barrel may be resulting in much less pressures than predicted.  I can't think why there'd be such a difference.

This does though reinforce the general findings that Quickload for some reason is not very reliable when using RS powders.  Sometimes it goes the other way (that certainly was my findings in both .308 and .223 with RS50).

However, for those wanting a roud which will stay happily above transonic to 1000 yards, 43 to 44 grains RS62 in a 24 inch 1/8 with Lapua 139 Scenars certainly seems to do the trick.  I may load some more up to 44.5 and see how they go.

Accuracy nodes were at:

41.4gr (2385fps) for a 0.5 inch group, vertical deflection of 0.47 inches;

42.9gr (2577fps) for a 0.64 inch group, vertical deflection of 0.58 inches;

43.9 inches (2613fps) for a 0.4 inch  group, vertical deflection 0.29 inches.

The above groups are very conservative as they were shot in less than ideal conditions with wind gusting to 12mph or more full, so on a still day I would expect to see those figures probably half.

Pluggin in the data for that bullet at 2613fps using a G7 profile gives a 1000 yd velocity of 1402fps which is mnore than adequate to keep things nice and stable, and in theory the bullet remains above transonic to  1175 yards and supersonic to 1275 yards.

I am disappointed with the velocities gained using RS62 so would be interested in what some of you may be achieving using N160 as I may switch to this and have a try to see how it compares with RS62.                                         

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Thanks for that insight. I too have looking at this powder for my new 6.5 CM and have been running the data through QL and take the results with a small-ish pinch of salt.  A couple of years ago when I was looking up data for my .308 target rifle, using RS52, the predictions were "Waaay off" suggesting I use 2.5 grains over what I actually needed to get to the velocity i was looking for. I have learned from this and now assume that what it suggests is merely a ball park figure, so when running up some test loads I make a large batch,  with a wide spread of powder loads, start at the bottom and make accordingly small or large jumps.

post up when you have better results

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Your velocities seem a tad low to me. I achieve just a little below QL predictions with RS62 in my 260.

Of course if you really want speed, RS60 is the way to go. Burns hot though.

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Remember the small primer / flash-hole effect on pressures and MVs compared to large primer results. In 308 Win, the norm is that 'Palma' brass needs somewhere between 0.5 and 0.7gn more powder to produce the same MV as the same internal capacity standard LR primer case with H4895 and H. VarGet class powders.

However, when I did side by side  tests of  SR primers in 308 Win (written up in Target Shooter online) with the 167gn Scenar and Viht N150, I started out with side by side load development using Lapua 'Palma' and standard cases in the same range session. I found with this powder which has a not dissimilar burning rate to RS62, that a 1.4gn heavier charge was needed in the SR Brass to get equivalent MVs. (the 260 is of course an LR primed case, so gets the hotter ignition.)

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Thanks for sharing your experiences chaps.  Laurie, the SR primer point is well made and not something I that had really put much thought to.  I'm quite surprised if the difference in ignition makes 150fps, but as QL has been quite accurate for other powder/brass/bullet combos I've used to date (other than RS!), as improbable as it might seem, then it has to be a material consideration, and as I've had next to no pressure signs, I could continue to load upwards and see what happens.  However, as I only shoot to 1000 yards, then 2600-ish is all that's needed with such a slippery bullet.  Perhaps trying some magnum primers such as the Remmy 7.5s or KVB-Ms might be worth a try  though as a more efficient means of achieving some MV gains through higher ignition energy?

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Only just bought some, but made sure I got 1000 whilst the getting was good!

I've done a little more development and the 2nd firing on new cases will see how fireformed performs over fresh brass.

Laurie's point is a key one though, and QL doesn't account for a change of primer to small primer brass.  This seems to drop pressures significantly and I'm probably down somewhere in the high 40K PSI range with my latest tests of 2630fps.  I'll need to load up in small steps to 45gr to achieve the velocities I'd get with LR brass, but one thing at a time, I'd like to load some more with Murom's magnum primers and see what happens.  I'll have the results by close of play next Wednesday.  I'll start a little lower to begin with at 43.5gr and load a few there and at 44.0, 44.3, 44.6, 44.8 and 45gr.  I should be able to find a good harmonic and velocity at that range.

I'm not after mega speeds and want the barrel to last, and the 139 Scenar is a very slippery bullet so only needs around 2600fps to perform well at 1000 yds.  However, one of the ranges I shoot at always has a very awkward wind swirls and thermal effects with surprisingly small cloud variations and temperature variations, so getting my horizontal drift as low as possible is important hence trying to squeeze 2700 to 2750fps as a decent target would be beneficial.

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The difference in windrift with between a 139gr scenar doing 2600 and 2750fps is around 6 inches in a 10mph wind

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That's about right, which is significant if in a comp. less so if not.  ES though is just as important.  I'd rather have single figure ES for a load than one with a few inches less wind drift but higher ES.  The difference between elevation points drop combined with wind drift can easily result in a point or two dropped compared with a load which has tighter velocity spread.  That's why I'm not going to overly stress about velocities but as I have the opportunity to work them up a little more as well as reduce ES, it's all part of the fun of learning with this small primer brass.

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I entered them speeds in but current temperatures reduced them quite a bit but it should be relative ish

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It's another reason why load development can't really be done at 100 yds as the apps are a useful tool, but until you have your "developed load" and test at distance (I like to use anywhere between 400 and 600yds) then verification of BC or MV becomes difficult and you still don't have precision until tested and found to be so.   That's why I think squeezing the smallest possible ES and consistency matters ultimately a lot more than MV.  The downside of course is that your wind/environmental reading skills need to be a lot sharper if you start out significantly lower than ideally where you'd like to be.  I prefer to look at that (initially anyway) as a positive but then again with only 18 months or so experience at very long range I may well change my mind about that after another few years!

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