Extreme Reloading the RPR: Optimal Charge Weight and Seeking the Sill (ep. 09)

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Here we look at load development for the Ruger Precision Rifle with optimal charge weight analysis and "seeking the sill" with both RL-15 and Varget for the Ruger Precision Rifle chambered in .308 Winchester.
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18 июл 2017

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Комментарии : 82

@sdkweber 6 лет назад

**** VOTING HAS CLOSED, WATCH FOR A SNEAK PEAK REVEALING OUR NEXT VIDEO SERIES **** Thanks for all who voted. I appreciate it!

@kjmdrumz3 3 года назад

Charge weight THEN seating depth.

@Bruce23d 10 месяцев назад

Great video!! Makes more sense to me now!!

@sdkweber 10 месяцев назад

Thank you Patriot.

@tv-cx8gv 2 года назад

Excellent video, wish I had seen it years ago!

@sdkweber 2 года назад

Thank you! I am glad you enjoyed the video. We are in a new season of Extreme Reloading now looking at bullets... seating depth, run-out, shape, etc. You might enjoy these as well.

@jessewerner4067 5 лет назад

If you're concerned about compressed loads...try vibrating your charged cases on a vibratory tumbler for 10 seconds before bullet seating. Seat your bullet 70% then flip case upside down and vibrate again, powder will fill in around the sides of your bullet boat tail. Finish seating. You'll be amazed at how much more powder you can fit in a case😁

@sdkweber 5 лет назад

I bet this would work. I have not tried it though. Thanks for watching and posting.

@wiggsan 3 года назад

Excellent video!! Still pertinent info!!

@sdkweber 3 года назад

Thank you Alex, and thanks for watching and posting.

@nomamartini1310 7 лет назад

I really appreciate you discussing the sill. I am conducting load development on a 75grain Lead Cast round and have found the sill between 1780-1840fps. After watching your episode, I tried conducting a bit more research on sill. Unfortunately, I haven't been to successful in find more information on sill. Can you provide references that would help me learn more about the sill? Thank you for your videos and your help.

@sdkweber 7 лет назад

Hello Knighthawk6 Thanks for watching and posting. "Sill" is a statistical term that describes exactly what we are seeing in the OCW process. Unfortunately, the term rarely used in the shooting community. I could send you some statistics stuff but not sure you are looking for this type of references.

@boomerrangerron Год назад

my vote is for 1911 reloading!

@AccurateShooter 4 года назад

Honestly, most folks who play with this OCW method achieve very little but wasting barrel and components. I advise starting with a premium, custom lapped barrel. Then research known powder & velocity accuracy nodes for the cartridge - such as 2950 FPS for a 6mmBRA. Then try seating depths .020 out for starters with a mag-fed cartridge. Shoot 3-shot groups with 0.3 gr increments up and down. If you start with a known node, you should have a good load within 40 rounds.

@sdkweber 4 года назад

Thanks for watching and posting. I have always ascribed to the idea of developing highly consistent ammunition to drive the accuracy. I am familiar with the harmonics approach and it is interesting. I think I will give some of this a try with my 168 gr. Sierra TMK bullets.

@kchanks1 5 лет назад

6.5 Grendel AR platform.

@sdkweber 7 лет назад

Arghhh!!! I noticed the voting/polling button is at the TOP RIGHT corner of the screen. Look for the (i) button. Sorry for the confusion.

@jimbiddle8646 2 года назад

Was trying to load 44 gr. Varget in new Lapua .308 brass. Wouldn’t fit . Thanks for answering my quandary.

@sdkweber 2 года назад

You are welcome Jim. And thank you for watching!

@N5KDA 6 лет назад

What is your issue with compressed charges other than broken power grains? I've found some compressed charges that shoot really well.

@sdkweber 6 лет назад

It's not that they won't shoot well, but there is the concern that those broken kernels can affect burn rate and cause sudden jumps in pressure. Thanks for watching and posting.

@scythes28 6 лет назад

While this is possible, some (like Varget) often shoot better (lower ES) with a slightly compressed load, at least that has been my experience. Also, you didn't touch on it unless I missed it, but ES is also extremely important at long range, not so noticeable under 500 or so though. While not common its possible to have bad ES in your sill zone. You might hit another sill a little higher if you aren't getting pressure signs, I had another around 44.1 of Varget in my rifle, with Winchester brass.

@sdkweber 6 лет назад

Very good to hear this scythes28. Not sure I talked about ES and its importance for long range shooting in this video but I am sure I talked about it in other videos. I have also mentioned (in other videos) that bullets can settle down after about 200 yards and really start showing their worth. Thanks for watching and posting.

@garyfoale3707 6 лет назад

scythes28 absolutely agree. I'm using 42.5gn of ADI2208 (rebranded to Varget in the U.S. I believe) in a .308. It's compressed under a 178 ELDx. My groups are the best I've ever achieved, though they're only moving at 2550fps.

@patdennis3751 5 лет назад

If short range shooting there's no issues.. However, as we all know, the farther out the greater the effect of variables.. When you crunch the kernels and thus increase burn rates, You are not doing this in a consistent manner from one cartridge to the next as the powder falls into the case differently from round to round. Thus your powder is burning at differing rates from shot to shot and giving fluctuating velocities.. Not an issue at shorter ranges, but for anything @ about 400 yds or so it begins to show up @@scythes28

@utdesertghost199 6 лет назад

Curious if you've tried alliant 2000mr? My Savage precision 308 was easily hitting 2700 with no pressure using a hornady 178 bthpm. Accuracy was very good, best 3 shot group was .187" easily held 1/2 moa through high and low temps. Also allowed for much greater range before going transonic due to the weight and high b.c.

@sdkweber 6 лет назад

Hello Phillip No, I have not tried that powder. I am going to look into it though after reading your post. Is yours Savage Precision a 24" bbl.? Thanks much for posting and watching.

@utdesertghost199 6 лет назад

sdkweber Yes it's a 10flcpk, I recently sold it and moved to a 6.5. But still have all my load data records.

@sdkweber 6 лет назад

My RPR is a 20" bbl so that will limit the muzzle velocity I am achieving. Thanks much for the followup. Good stuff.

@utdesertghost199 6 лет назад

sdkweber www.thetruthaboutguns.com/2013/10/daniel-zimmerman/the-truth-about-barrel-length-muzzle-velocity-and-accuracy/ Check out the above link, This one of the reasons I went with the 178 honady, not to mention the impressive b.c.

@calisg1010 7 лет назад

How long is your barrel? I shoot varget 43.0gr and get 2645fps with a 26in barrel 1-12 twist

@sdkweber 7 лет назад

Hello Shawn This is a 20" barrel with 1:10 twist. What you are getting jives pretty well with what I am seeing. Thanks much for posting.

@trumpie5399 5 лет назад

WW brass has more capacity 168 MK @ 46.0 of Varget CCI br2 Upper OCW load node Your load is the lower OCW load @ 43.9

@sdkweber 5 лет назад

This is a good point. OCW needs to be established using specific brass as some will have higher or lower case capacity, thereby changing the OCW. I like Lapua and Norma. Loads beyond what I tested here are compressing too much. Thanks for watching and posting.

@nomamartini1310 7 лет назад

Is there a load that it more accurate than the other? In other words is there a specific speed that the bullet is more accurate?

@sdkweber 7 лет назад

Good question. Throughout the range of charges tested, this rifle with the Sierra 168 gr. TMK has done very well (sub-MOA). The 42.9 gr. arrived at here will pretty much guarantee me 0.50 MOA or less from prone. In fact, just last weekend I shot a 0.47 MOA group at 300 yards from prone and I think I can beat that. I need to load another box and run another test but I feel very confident with this load. Thanks for watching and posting.

@jeromyknepp6643 6 лет назад

I really like 44.0-44.5 of RL15. But my current accuracy load for my .308 is 41.5grns of AR Comp and a 175grn TMK in RWS brass.

@sdkweber 6 лет назад

Tell me more about what you are getting with this load? Velocity? Precision? Where are you finding RWS brass and how does it compare with Norma or Lapua? Thank you very much for watching and posting.

@jeromyknepp6643 6 лет назад

sdkweber The RWS I bought through MidwayUSA sale on RWS hunting ammo. I shot it out and the did brass prep. I feel it is the same quality as the Norma I have used in the past. Velocity out of a 28” 1:12 is 2769 with and SD of 2fps. It’s a very consistent powder.

@jeromyknepp6643 6 лет назад

sdkweber After about 2000rnds the barrel is holding .3moa.

@sdkweber 6 лет назад

Very good stuff indeed. I am going to look into getting some RWS and maybe try a pound of AR comp as well.

@sdkweber 6 лет назад

Excellent. This is 5-shot group?

@RetrieverTrainingAlone 3 года назад

The sill is desired and important because powder performance may vary with temperature and throat erosion. By using a powder charge within the sill, these effects may be minimized. However there is variation at any specific load because the scale accuracy may be +/- .1 gr, there is variation in hand loading components, the chronograph accuracy may be +/- 5 fps, etc. So it is possible to get an "artificial sill" due to inherent errors in measurements and hand loads. These variations are not accounted for due to a sample size of 1 for each powder load in the 10-shot OCW method. One approach is to shoot the 10-shots from low to high powder charge, then repeat for a sample size of 2 by shooting the 10-shots from high to low powder charge to confirm that the sill is not "artificial". Or shoot the 10-shot OCW each day for 3 days in a row to see is the sill "artificial" or is is consistent and real? In your example, you got a consistent sill based on 2-powders, so it is likely real. "Extremely consistent muzzle velocity" requires an adequate sample size for a specific powder load. In the 10-shot OCW method the sample size is 1, so the variation of muzzle velocity at a specific charge is unknown. After discovering the consistent sill, shooting 5-shots at a powder charge below, within, and above the sill would show how consistent is muzzle velocity at a specific powder load.

@sdkweber 3 года назад

You are right. It is important to verify by additional testing.

@RetrieverTrainingAlone 3 года назад

@@sdkweber As an example, I shot 4 10-shot ladders yesterday with a Tikka .270 Win and 4350, each sill was less than 3fps but different: 53.7, 54.3, 54.7,53.5. I shot at 0 degrees C and let the barrel cool for 5 minutes between shots. Used a magnetospeed chronograph. I think the differences were due to inherent variation due to powder and chronograph errors (+/- 0.1 gr?, +/- 3fps?) and variation in hand loads. Ultimately I selected the charge with minimum velocity variation 54.5 (stdev 4.0, n=4).

@sdkweber 3 года назад

@@RetrieverTrainingAlone I would have done the same thing. But also look at the harmonic nodes while shooting the ladder. If you get a sill + harmonic node at pretty much the same powder charge, that will be a hard load to beat.

@RetrieverTrainingAlone 3 года назад

@@sdkweberI like the school of thought to first minimize velocity variation (ignition variation) by trying different powders/primers/neck tension, etc. Then work on the harmonics via different bullet seating. See Eric Cortina's video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6VEMZJYovMA.html

@sdkweber 3 года назад

@@RetrieverTrainingAlone I think you will like our new season of EXTREME RELOADING. We are focusing harmonic nodes and neck tension. I call it "Nodes, Necks, and Sills" and the first video will be released in about a month.

@davejan744 6 лет назад

Just found your channel, subbed. Also just found out the military is changing up to 6.5 CM over the standard 308. If artical is correct basically rebarrelling service wide. Superior ballistics yada yada yada. With THAT happening the 6.5 ammo is going to also be mass produced cutting its costs radically. (Outrageous now.) Just food for though for future vids. BTW, Ive been loading for 40 years & learned something new today. Thank you! Also, by doing the internal primer hole reaming I changed my 30-40 FPS variations down to 10 FPS variations. Im absolutly anal about EXACT charge weights. Every new rifle gets the battery of powders, primers, bulletts until I find that ONE load sweet spot & that rifle shoots only that load from then on. If I know my rifle is shooting straight, I SHOOT straight. Personality mental quirk....

@sdkweber 6 лет назад

Thanks Dave Jan, I did not know the military was going to start using the 6.5 Creedmoor. I need to look into that. Also good to hear the flash hole tip helped you. I agree with you that if you have confidence in your rifle you tend to shoot it better. I think that is true for everyone. Thanks again for watching and posting.

@jamesdean8809 2 года назад

Try the new 169 SMK. It stays super sonic to 1100 yards

@sdkweber 2 года назад

I am using the 168 gr. Tipped Match King which has an even higher BC. The killer is not the point at which these bullets drop below the speed of sound but the point at which they enter the transonic zone (~1300 fps and below). Sierra Match Kings are somewhat notorious for not flying through that zone very well. Thanks for watching and posting. I always like to hear about newer bullets!

@jamesglenn520 3 года назад

I know this is an old video but. I'm curious to know with the 2.79 OAL how far off the lands is it? And would you have any information on reloading a 165gr bullet or personal experience for long range? I have an RPR Gen2 308 and I inherited a bunch of 165 308 bullets. Any bit of information or advice would be Absolutely Appreciated 👍👍

@sdkweber 3 года назад

Hello James, In my experience with the RPR it does not perform well with the bullet seated very close to the lands. I load the Sierra 168 gr. TMK to fit into the magazine (pretty close) and that gives me 0.7 MOA groups very regularly. However, If you use a bullet with a secant ogive these are going to be more sensitive to seating depth relative to the lands. I did a few videos on 165 gr. bullets in the RPR, here is a link ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-39gxq0The_c.html to the first one. I used the Sierra Game Changer and then also tested this against the 165 gr. Barnes TTSX bullet. Thanks for watching and posting.

@jamesglenn520 3 года назад

@@sdkweber With 2.79 do you know how many thousandth you are off the lands?

@jamesglenn520 3 года назад

@@sdkweber Thanks for the link it really helped me to find a starting point 👍 I am just curious about how much Jump your rpr seems to like. At this time I really don't have the equipment to measure the chamber correctly 😒

@sdkweber 3 года назад

@@jamesglenn520 Hello again James, I took some time to measure all this again last night using some relatively new Hornady tools I have. If I were to seat a bullet just a few thousandths off the lands the cartridge would never fit into the magazine. The load I worked up actually has a 0.180" jump from the ogive of the bullet to the lands. That is tremendous but giving me 0.7 MOA groups consistently even out to 600 yards.

@jamesglenn520 3 года назад

@@sdkweber That's a Hop Skip and a Jump!! I'm hoping to make up a load that is fairly consistent with these 165gr that I have. I truly do appreciate your time in helping out 👍👍 I just can't see not trying to use these bullets for quality trigger time. But I think it would be a waist to just randomly load some Crap Load that just goes Bang!! Lol Plus some are Hunting bullets so that would be a plus for that.

@toddb930 6 лет назад

How many rounds did you fire at each charge weight?

@sdkweber 6 лет назад

With well prepared, high quality brass cases, you only need to fire one round at each charge weight to locate the sill. Seems to work pretty well. Is it perfect? No, but it certainly seems to help with load development. Thanks for watching and posting.

@toddb930 6 лет назад

When you have some extra time would you mind trying to repeat 4 of the charge weights with 5 rounds each? From my experiences when stepping at 0.2 grains and measuring each powder charge on a scale that has a resolution of +/- 0.05 grain, I measure velocity which can overlap velocity of an adjacent charge weight.

@sdkweber 6 лет назад

Hello Todd B. This is a good idea. I think one would still need to take the mean and/or median velocity of those 5 rounds, or just plot all of them as a scatter plot "cloud" to understand what is going on. I wanted to share with you though the "proof in the pudding" for the OCW process. The video that followed this "seeking the sill" video, shot a group using the powder charge indentified here. We got a muzzle velocity standard deviation of only 3 fps., check out this video if you are interested at ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-yuq0zbJI5zQ.html Also, the RCBS electronic scale has a tolerance of +/- 0.05 grains, so measuring at 0.2.gr. is a real measurement and not within the instrument's error tolerance (I had a long discussion with RCBS on this and saved their emails). Thanks again for watching and posting.

@Rico11b Месяц назад

I realize this video is old now, but this isn't really the OCW method. The OCW method by Dan Newberry isn't based on muzzle velocities. Velocity driven "flat spot" load development is a losing endeavor and doesn't really have anything to do with the OCW method. Leave the Chronograph at home and let the target tell you what is the best load.

@sdkweber Месяц назад

There are many variations of these methods (OCW, harmonic node, ladder) and none are perfect. I use the velocity sill instead of using 3-5 shot groups on target. I do not disregard the target but my primary emphasis is on reducing variability of muzzle velocity with the load. I will never say my approach is the only approach that should ever be used but encourage others to find a method that works for them and their rifle.

@billcarlson852 Год назад

5.56

@FuelTankerMan 5 лет назад

I trust your reloading system is working well for you, and others. That said, OCW and "Optimal Charge Weight" are my intellectual property. The OCW test as properly conducted can be seen here, at this link: OCWreloading.com

@abcertweld 6 лет назад

Lol 950yrd shot is far for a 308 lol that's news to me lol. A 308 is a 1000 yrd rifle all day long easily from my own personal experience and many other's.

@sdkweber 6 лет назад

I am curious, what bullet are you using and what muzzle velocity are you getting? This 168 gr. goes trans-sonic at around 950 yards.

@abcertweld 6 лет назад

sdkweber I will tell you what bullets I use Hornady 178 BTHP Match Alco 175 Both are over 2,700fps at the muzzle.

@sdkweber 6 лет назад

That bullet will do it out to 1,000 yards and more due to its BC and the muzzle velocity you are getting. I never had good luck with the heavier bullets in my RPR. It really likes the 168 gr. bullets, so that is what I use. Thanks for watching and posting.

@abcertweld 6 лет назад

sdkweber that's to bad. I've always found it funny how a gun likes a particular bullet more than another and two can be the same. I tell people that and lol they look at me funny lol. I guess they are just regular shooters or haven't really evaluated different bullets in different calibers. Nice channel. I'm building a new 308 like I need another lol. Just joking it's for my son. I'm going to use it to test out the Hornady 225gr. BTHP Match it's BC is .777.I'll try to see how fast I can push it with my powder combinations and mixtures. P.S. and by that I mean safely.

@sdkweber 6 лет назад

I suspect you are going to need a very fast twist to stabilize a 225 gr. bullet in the 308 winnie. Hornady's site does not give a recommendation but you will likely need a 1:9 perhaps?