308 OCW test 175 SMK Varget vs IMR 4064

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Minuteman
Mar 31, 2010
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Stuck in Kalifornia
#1
Relatively new to the forum. Please excuse me if I'm not getting pics in correctly or something.

Ran an OCW test yesterday to compare Varget with 4064 on Lapua brass, Fed 210M & SMK 175s out of a stock Rem 700 SS 5r 24".

Learned about the test here:
OCW Load Development

First time trying this technique.

Here are my results. I did 3 shot groups to make it easier to cover the range of charges, 5 would have been better and what I plan to do from now on to dial in the sweet spot.

Also this was at 100yrds. Would have liked to do this at 200 or 300 but hard to find a range with that dist around where I live.

Had a few challenges with my crono, not the best piece of equipment but works (most of the time).

Still, with all those caveats, the 4064 seems to have produced a pronounced sweet spot with the SMK 175 in my rifle. Varget not so much.

Any thoughts from you guys? Love to hear any advice or commentary on my testing technique.

Thanks!

308ocw_imr4064.jpg


308_ocw_varget.jpg


Updated 5/31 with POI scans.
 
#4
Re: 308 OCW test 175 SMK Varget vs IMR 4064

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: flyboy</div><div class="ubbcode-body">Best 175 MK load for my 20" remmy is 45.5 IMR 4064. Get me 2600fps and very accurate. </div></div>

What kind of 20" Remmy? Factory SPS-T chamber or custom chamber? I have a can of 4064 laying around I've never opened and have been contemplating working up some 175SMK loads with it.
 
#5
Re: 308 OCW test 175 SMK Varget vs IMR 4064

All all 20 3-round groups small enough and round enough to be worthy of consideration?

Both powders appear to be generally charge weight tolerant with that bullet.
 
#6
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Grump: All 20 groups were pretty much under an inch. In both powders the higher velocities (2600 or above) produced tighter groups than the slower velocities. That is consistent with what I've read about .308s liking near 100% loads. Several of the fastest strings had three holes touching.

Having said that 3 shot strings aren't really the best way to determine grouping.

So to perhaps answer your question: I overlaid the targets for strings 6,7,8,9 of the 4064 and 7,8,9,10 of the Varget. Both 12 shot groups are just about 3/4" for both powders. That seems pretty good to me considering the charge weight range across those dozen shots.

I'd say both powders are clearly capable of accuracy in this rifle with this bullet. At 100 yards anyway.
smirk.gif


The real difference just might might not show up until the long range. I need to get out there and try it.
 
#8
Re: 308 OCW test 175 SMK Varget vs IMR 4064

My best load, for my rifle, is 44.5 grains of 4064, FED 210M, OAL 2.872", with the 185 Lapua Scenar, HxBN coated. Vertical at 400 yards is less than 1/2 inch. Horizontal is dependent upon me and the wind. Gotta learn more about that. JMHO
 
#9
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Still playing with that. I used to be after almost every outing or every 100-200 rounds, from the old Highpower days.

Might have been close to 300 last time. Ammo development with 155s just wasn't going anywhere, so I succumbed and cleaned.

Didn't make a difference. For the 155s or my current reference load with 175s and 178s.
 
#11
Re: 308 OCW test 175 SMK Varget vs IMR 4064

To me: you have not peaked out on the vertical indicator with Varget--that is there is no obvious flat spot over several CW steps. We do see this in 4064.

However, 2650 is a fine velocity for 175 SMK and not much reason to push it much harder.
 
#12
Re: 308 OCW test 175 SMK Varget vs IMR 4064

What's your elevation? Just curiuos cuz the velocities are lower than what I am seeing out of my 24" savage. My 'go to' load is 43.9 grains of varget , lapua brass, 2.815COAL, and I saw a 2745fps average velocity. But I am at 2700 feet and the brass was virgin...
 
#13
Re: 308 OCW test 175 SMK Varget vs IMR 4064

werks: about 600ft. This was virgin Lapua as well. I plan to shoot the test with Varget again this weekend and see if I get the same result.

Thanks everyone for the replies. I'll see if I can get pics of the groups posted.
 
#14
Re: 308 OCW test 175 SMK Varget vs IMR 4064

IME and rough physics analysis, altitude really doesn't affect muzzle velocity, except for the very, very small number attributable to drag between the muzzle and the chrono screens. (Instrumental vs. true muzzle, but JBM adjusts for that anyway).

Some barrels are "faster" than others. Speed always comes with a price--pressure. It's not a straight line correlation, but I trust QL pressure estimates when fired case capacity, fired case length (don't forget that one!), bore information, and actual tested velocities are used to fine-tune the burn rate.

The most important factors IMO are case capacity and observed velocity. I'm not currently convinced that adjusting only the Ba value by itself if the best approach and suspect that progressivity might need concurrent adjustments to get the best low-to-high estimates and prediction.

Looking at the VALUES of the not-so-flat spots on the Varget velocity chart, 3 points in 20 fps, followed by four points in 40 fps, both appear "flat" enough for charge weight tolerance. The vertical distance chart, even considering magnitude of differences, is not encouraging and I would caution against seeking more velocity with any powder with that barrel length and bullet.
 
#16
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Ran this again yesterday with both powders and tried to narrow down to a range of powder charges that made sense from the first test.

Used 5 shot strings this time. Images of groups attached. Forgot to annotate, this is all at 100 yards.

To my untrained eye for the SMK 175 in my barrel the Varget with charges between 44.5-44.7 is maybe a good choice. Maybe split that and go with 44.6? Only 2 fps across that range and the vertical dist across both groups is tight. I do not like what I saw above and below that range in the Varget however.

The 4064 did produce some tighter groups and less vertical dist across all 5 charges and a little higher velocity but the velocity variation is higher. I would think that's more of a problem when I get to start shooting longer distances.

It's really hard for me to see if there is a clear choice from this.

Anyone care to share an opinion?

Thanks in advance!

-d

ocw_varget_5-29-2010.jpg


ocw_imr_4064_5-29-2010.jpg
 
#18
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Your test look good IMO don't sweat the group size we are just looking for POI 44.6 Varget is looking interesting. If possible to confirm select three load bracket and shoot one round each at 300yds, they should all be close. Then play with the selected OCW round seating depth both in and out to tune the harmonic in for smallest group. Nice work
 
#20
Re: 308 OCW test 175 SMK Varget vs IMR 4064

ewoaf thanks, I've read that. Very interesting. I saw 42.2g 4064 for the 175 smk being proposed. Estimating from my earlier tests 42.2g of 4064 in this Lapua brass, 210M and my tube would be about 2570fps. I'm hoping to find an accurate load with these components over 2600.

Unsichtbar: yeah I'm liking the Varget at 44.6 too. Sadly without driving for a bit the longest I've got anywhere around here is 200 yards. Hoping to get there next weekend. If I do I'll be trying your test.
 
#21
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Funny, just did OCW with 175's and Varget, 44.6gr. was a happy spot for me using CCI BR4's in Fed GM brass. 2715FPS outta Savage 10fp w/ Lothar-Walther Barrel. I started .02 of the lands, then moved in .01 increments till I hit the lands. They like it on the lands. Once I got there the SD went to single digit. Hopfully it will stay there during further testing.
 
#22
Re: 308 OCW test 175 SMK Varget vs IMR 4064

With the Varget target, it looks like your scatter group is at 44.3g (due to different POI), so that would make your OCW node about 1% higher or 44.7 or so. I think your target bears that out. The POI of the groups at 44.5, 44.7 and 44.9 are all very similar. I would call your OCW at 44.7g and work with OAL until you find your "load".

I do not think the IMR4064 target is as clear. The POI between the 44.3 and 44.5 groups looks similar. I see know clear scatter group however. If I was going to keep with IMR4064, I would load up some at 44.4g and play with seating depth.
 
#23
Re: 308 OCW test 175 SMK Varget vs IMR 4064

.15 inch difference in center of group impact isn't a lot. Less than .05 mil, or roughly .6 of a click on a quarter-MOA scale.

That's the difference between the two "flat" spots on impact for 4064. That's also only 32 fps spread in the mean velocities for the four charges from 44.1 to 44.7, so it looks like a second test is needed to make sure you're not inside OR outside the random variations possible with this situation. Don't bother with that lowest charge weight.

Varget is similarly close in velocity spreads, averages over the top four being a whopping 33 fps. Once again, I'd re-test with the four higher weights.

For some real fun, shoot two, five-round groups with each powder, with one charge from each weight, and a fifth at the mid-point. Chart impacts vs. charge weights and you might get some surprises.

Load development can be a pain, but it appears from your posts and your approach that you really want high confidence in your data.
 
#24
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Ran your test Grump. 4 highest loads + 1 load in the middle of that range.

Btw, you are right I like data and I like to understand it. I really want to get where I can see improvements in the data so I know something is actually improving when I change it.

Below are the 5 loads using 3 shot strings to help average out my poor shooting.

Please throw any more feedback my way. Really appreciate it from all of you.

ocw_varget_6-6-2010.jpg


ocw_imr_4064_6-6-2010.jpg


Note I had some problems with the chrono when I shot the 4064. Sun was starting to hit it dead on and I think that threw my readings high (and maybe caused the spread to be off too). Didn't realize until after I shot and went out to get the chrono.

Here is 3 5 shot strings of each midpoint load:

Still liking Varget 44.6 particularly with the tight velocity spread above.

varget_44.4_5-shot.jpg


imr_4046_44.4_5-shot.jpg
 
#25
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Interesting that your 4064 loads are more consistently tight with 3-shot groups, but open up with the 5-rounders. Am I seeing an opposite effect this time with your Varget loads?

Sorry I didn't make it clear, but I was trying to suggest two, five-round groups, using one round each of each of the four charge weights (plus the midpoint charge to make five) in each string. IOW, string 1 would be shot 1, 44.1 Varget, shot 2, 44.3, and so on. Even if you didn't track each shot's impact on the target, the total results might bring some comfort regarding the importance of charge weight variations with each powder, that bullet, and your barrel.

Since you're not chasing benchrest, I'd say you're probably pretty safe with either powder. I'd go with 44.5 on 4064, and 44.7 with Varget. To settle on which one, or determine that you have two good loads, hold onto 15 of each and test them at 600 or further out on your next perfect no-wind cool low-mirage morning, at a real highpower range with someone pulling targets so you can chrono at the same time and see for yourself how much or how little the velocity variations throw your 175s.

Alternate 5 rounds with each load, take copious notes, and have your puller use two different colors of 3/4" or 1" round sticky labels to mark shots from each load, and write a number on them as he/she pulls the target.

You may have some shooter fatigue coming into play with this last test.

For grins and giggles, also do one five-round test of the spread-out charge weights at 600 or further out. Then you will KNOW how charge-weight tolerant each powder really is out of your rifle.
 
#26
Re: 308 OCW test 175 SMK Varget vs IMR 4064

If I can put 2 suggestions :

First of all, maybe me sentences will seems to be rude, but it is not intentional, just lack of right way to say my minds.
<ul style="list-style-type: disc">[*]Doing myself some ladders and some OCW tests, I think that 100y/100m is not enough distance to bring in light loads differences. I prefers 200m. More than 200 will see some aerial interferences (mirage, wind, poa shift) pollute your tests. [*]It seems to be some flyers in most of your groups, perhaps trying to let another shooter doing the test can be an idea.[/list]
 
#28
Re: 308 OCW test 175 SMK Varget vs IMR 4064

Ah I did misunderstand that Grump. I'll give that test a run just for fun. I think you're right though both powders in this range are giving me fair results (for my skill). Yes I was getting a bit fatigued on that last test. By the time I got to that set I had guys moved into the lanes on either side of me who started pounding away with braked AR-10s. Still learning to tune that out.

One more thing I forgot to mention. My first set of tests in this post were with virgin Lapua brass. This last set of tests was with once fired and FL resized. The fired cases ended up about .005 longer measured with a headspace gauge and fit my chamber quite snug. I suppose it's possible that slightly higher case volume could result in some change in velocity for the same CW in the two set of tests that could have affected the results. Managing headspace, just how much to bump the shoulder, etc. is an area in my reloading skill that I'm still working on.

Jp: no offense taken. I know some of those flyers are me. I've been hoping using averaging I can remove some of that. I think that sorta worked in the larger charge weight range tests. However getting down to the finer tests I'm probably introducing a lot of "noise" into the POI data that makes it hard to see differences in the powder charges. Particularly at 100 yards as you correctly say.

It may be just time for me to get out there and shoot a bunch with either of these two loads to work on my technique some more. There's a real high power range about 2 1/2 hours away. I've been wanting to get dialed in a bit before going out to play with those guys. They have practice days 1st Sat of each month so next month I hope to get there.
 
#30
Re: 308 OCW test 175 SMK Varget vs IMR 4064

JpS, true OCW tests are shot round robin to cancel out some of the "aerial interferences" to which you refer. Secondly, he is not shooting VLD bullets, so yaw and the bullets "settling down" are not an issue with his choice of bullet. For these two reasons, I believe that 100 yards is a better distance for testing to find his OCW load.

Diamond, I think your reshoot settles things out quite nicely for you. I agree with Grump on the OCW charge of 44.7g with Varget, but think 44.5g of 4064 seem about right. I also agree that you need to get out to distance and see how your vertical with the two loads pans out. I think the Varget load would be what I would settle on due to less temperature sensitivity of the Hodgdon Extreme powders.

Good shooting and thanks for continuing this thread.
 
#31
Re: 308 OCW test 175 SMK Varget vs IMR 4064

http://practicalrifler.6.forumer.com/viewtopic.php?t=1164&highlight=175+smk+varget

This is a OCW test for Varget 175 smk shot with a 20" barrel, fo course you should shoot your own test but they should be simular in some of the finding. Take a look at the other post on this site, run a search for 4060, there is a test for that also. IMO and experence shooting at 100 for a OCW test works best, then move back to confirm, then test for seating depth.
 
#33
Re: 308 OCW test 175 SMK Varget vs IMR 4064

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rth1800</div><div class="ubbcode-body">I have seen more lot to lot varation on Varget than I have temp varation on IMR 4064. JMO </div></div>

Buy an 8 lb jug.
 
#34
Re: 308 OCW test 175 SMK Varget vs IMR 4064

8 lb x 7000 grains per pound=56,000 grains / 45 grains per round = 1,244.4 rounds = 2 mos of shooting. Then re tune load for new lot.
In my opinion, IMR 4064 is the answer. I back off .5 grain for summer loads. I would also say that Varget is over rated for it's heat/cold stability. It is hard to quantify due to the lot to lot variation. It was pushed by MFG as it was the 'new thing" when it came out. Sold well to the guys just starting in RL due to the hype. For the guys who had thier IMR 4064 loads and a brain, it was a flash in the pan, parden the pun. Do not get me wrong, Varget is a workable powder, but given a fair trial, it will seldom equal IMR 4064 in any aspect. JMO
 
#35
Re: 308 OCW test 175 SMK Varget vs IMR 4064

My 4064 loads showed a 20-fps or so *reduction* in MV from 40-60F to 80F, two separate days at 80...

Isn't that what Varget is supposed to do sometimes???
 
#37
Re: 308 OCW test 175 SMK Varget vs IMR 4064

granted im new to this but just did a very similar test last summer and with very strikingly similar results using the 4064. i dont know about varget but i read your results the same way i read mine. 43.5 grains of imr 4064 is awesome under the 175smk. your groups seem to verify it to me, but the 26" bbl savage i was using ran 2690ish fps at that charge with m118lr brass. so maybe it is that speed thats a "node" and it takes more charge to achieve it from a shorter barrel and different brass. for me this charge weight runs same as m118lr factory velocity wise. i too noticed weird lower poi the faster they ran in some cases due to harmonics id say. anyway i tested the 43.5 in that stick out to 725 yards with pretty good (moa) results in a lot of wind.
 
#38
Re: 308 OCW test 175 SMK Varget vs IMR 4064

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kyreloader</div><div class="ubbcode-body">JpS, true OCW tests are shot round robin to cancel out some of the "aerial interferences" to which you refer. Secondly, he is not shooting VLD bullets, so yaw and the bullets "settling down" are not an issue with his choice of bullet. For these two reasons, I believe that 100 yards is a better distance for testing to find his OCW load.
</div></div> When I suggest using 200y rather than 100y as OCW distance, my main argument is that the longer the distance is, the more it reveals differences between shots of the same load but aerial interferences (as early said) produce more interferences than loads at longer distance, so my preferred distance, for OCW is 200m.

Regarding shooting process, i do agree that an OCW have to be shoot rond robin otherwise it is a ladder test.
 
#39
Re: 308 OCW test 175 SMK Varget vs IMR 4064

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rth1800</div><div class="ubbcode-body">I have seen more lot to lot varation on Varget than I have temp varation on IMR 4064. JMO </div></div>

Interesting. That is one of/the main reason my brother recently stopped using Varget in his 308. Though it's heresy to so many here, he's found better consistency out of 748. Myself, I only just got my first-ever 308 this month, so I haven't the direct experience yet. It's just interesting that what you're saying and what my brother tells me matches so well.
 
#42
Re: 308 OCW test 175 SMK Varget vs IMR 4064

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kyreloader</div><div class="ubbcode-body">Buy 6-8 lb jugs of Varget from same lot.

I just dont see the utility in changing my loads based on what temperature it is outside. </div></div>


Am I the only one that buys three 8lb jugs then mix them all together in a 5 gallon container and then seperate them out back into the 8lb jugs?

This will make sure that you have 24lbs of powder that is the same.
 
#43
Re: 308 OCW test 175 SMK Varget vs IMR 4064

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nessal</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kyreloader</div><div class="ubbcode-body">Buy 6-8 lb jugs of Varget from same lot.

I just dont see the utility in changing my loads based on what temperature it is outside. </div></div>


Am I the only one that buys three 8lb jugs then mix them all together in a 5 gallon container and then seperate them out back into the 8lb jugs?

This will make sure that you have 24lbs of powder that is the same. </div></div>
If your county has the last version of the Uniform Fire Code I looked at, you're getting into the territory where 1-inch thick wood-walled storage magazines and maximum quantities per box are, um, required for in-home storage of such propellants.

It might matter to your insurance carrier. I suggest you check your policy.

But yeah, I blend. Just with smaller batches of powder. For precision rifle. Doesn't seem to matter with W-W 231 and 296, Unique, and other pistol stuff.
 
#44
Re: 308 OCW test 175 SMK Varget vs IMR 4064

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grump</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nessal</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kyreloader</div><div class="ubbcode-body">Buy 6-8 lb jugs of Varget from same lot.

I just dont see the utility in changing my loads based on what temperature it is outside. </div></div>


Am I the only one that buys three 8lb jugs then mix them all together in a 5 gallon container and then seperate them out back into the 8lb jugs?

This will make sure that you have 24lbs of powder that is the same. </div></div>
If your county has the last version of the Uniform Fire Code I looked at, you're getting into the territory where 1-inch thick wood-walled storage magazines and maximum quantities per box are, um, required for in-home storage of such propellants.

It might matter to your insurance carrier. I suggest you check your policy.

But yeah, I blend. Just with smaller batches of powder. For precision rifle. Doesn't seem to matter with W-W 231 and 296, Unique, and other pistol stuff. </div></div>


This is precisely what I love about the Hide. In reading this thread I was learning a great deal about OCW which I'm working through with both my .308 and .223 right now. Then as the thread goes off on a tangent I learn that Varget may not be the end all powder it's marketed to be(which I've bought into lock, stock and barrel) and that buying bulk powder and blending it will make for more consistency......it's really cool just how much info (good/bad/etc.) you can be exposed to in short order. What a wealth of knowledge.
 
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