Initial Load Development Lapua Scenar 120 gn and Leverevolution using GRT

[SCJim]

A few months back I bought 1000 Lapua 120 gn Scenars specifically for my 6.5 Grendel but never got around to it until a few days ago. Looking through my powder locker I noticed I had several pounds of Leverevolution powder so I decided that would be the powder I would start with. Official sources for 6.5 grendel load data for both the powder and the bullet is scarce as hen's teeth so I had to use internet postings, Quickload, and Gordons Reloading Tool. I personally prefer GRT over Quickload so I decided to use it for the development,but that is purely a personal preference. Bearing that in mind, here is some legalese

CAUTION: The following post includes load data generated by calculation in Gordon Reloading Tool (GRT) software is based on particular powder lots, the assumption the primer is as mild as possible, and assumptions about component, chamber and gun geometry that may not correspond well to what you have. Such data should be approached by working up from published starting loads. USE THIS DATA AT YOUR OWN RISK. Neither the writer, nor GRT's author assumes any liability for any damage or injury resulting from use of this information or information derived from it.

One of the first steps in using any ballistic software is putting all the parameters from your rifle into it. Barrel length, twist, gas port size and location etc come into the equation and can affect the outcome. GRT seems to be on the conservative side but do use common sense and caution and check for overpressure signs at every turn.

To find a good starting point I spent a few hours Googling looking for others who have posted about using Leverevolution in the Grendel and 120 class bullets. This load will be used to shoot a maximum of 850 yards so I need to be able to stay above Mach out that far at least. That means a muzzle velocity of at least 2450 using Lapua's BC numbers. Once I had a starting point and had entered all my variables regarding my rifle I figured a load somewhere between 28 and 30gn of powder should do the trick. Rounds were loaded to magazine depth of 2.26 inches. Primers are Federal AR Match. The rifle has a Rock River Match lower, upper is garage built using Aero receiver, bolt and handguard. Barrel is a Wilson Combat 20 inch and the scope is a Sig Sauer 4.5 - 14, bipod on the front and squeeze bag rear.

I set my Shotmarker and here are the results. The adjusted FPS is muzzle velocity calculated using the the JBM software by posting the distance from chronograph where the readings were taken. In this case 100 yards.

[ATTACH=CONFIG]19029[/ATTACH]


Keep in mind that the velocities are computed by the Shotmarker at 100 yards. To get the muzzle velocity I took the velocities on the target and used the JBM Ballistics web page to adjust the numbers for muzzle velocity. I put the numbers into a spreadsheet and the first thing I noticed was that Leverevolution gave me a very flat velocity curve

[ATTACH=CONFIG]19030[/ATTACH]

The first thing I noticed was there are two distinct flat spots in the graph. The first is at 28.5 to 28.8 the second is at 29.7 to 30.0. Looking at the target the 28.5 and 28.8 group sizes were also very tight (for me with a AR) so my next step will be shooting @28.5, 28.6,28.8.and 28.8 and evaluate from there. I may tweak seating depth and primer choice to further fine tune once I confirm a final charge weight

[Old Bob]

Were there any over pressure signs during your evaluation?

[SCJim]

Were there any over pressure signs during your evaluation?

no ejector marks, primer were rounded with no cratering. Being as this is a gas gun, I would not expect to see overpressure signs on the brass, far more likely I would damage the bolt first. Brass aside I go by velocity for determining overpressure warnings and my cutoff was at 2550 FPS. GRT had overpressure (50K plus) beginning at around 29.7 but since my brass and primers looked good, and the bolt and reciever are new and of good quality. I decided to chance it shoot those last 5. It was a judgment call and probably not the wisest thing I have ever done. I would have stopped at 29.7 if that had I been using a lower quality components, hence my warning and disclaimer in the first post.

That is also why I will drop back to 28.5 to 28.8 for my load workups. It will put me over 1200 FPS @ 800 yards for tripping the electronic targets and bullet stability and will be a bit easier on the brass and the rifle.

[LRRPF52]

You should be able to work up to 31gr of LEVERevolution under a 120gr Scenar-L, provided you don’t have an unusually-short chamber.

I’ve done a bit of work with 123gr SST and 129gr SST with that powder and went much higher than what you’ve done.

LEVERevolution is one of the most forgiving powders for 120-130gr class cup and core bullets in 6.5 Grendel.

Your barrel length and gas system length should allow optimum balance between velocity and gas system timing.

I noticed kind of erratic and excursion-like readings once I got over 31.0gr under the 123gr SST, with departures from the trend in velocity relative to charge weight.

22” barrel
Federal brass 1x fired
1.208” headspace to datum line on mid shoulder
Rem 7.5 SRPs
LEVERevolution
COL 2.250”
60 degrees F

29.8gr 2453fps
30.1gr 2465
30.4gr 2499
30.7gr 2517
31.0gr 2534
31.3gr 2596 (I would not produce these loads based on what I saw initially.)
31.6gr 2608
31.9gr 2605
32.2gr 2658

Notice the 62fps jump from 31.0 to 31.3gr. This was just a single pressure ladder to check the safety range and establish a trend line base with that bullet/brass/primer/COL combo.

If I were to test it some more, I would extend the COL out longer and probably wouldn’t load past 31.2gr.

I have shot a lot of 120gr Scenar-L in the past, and it’s a very accurate bullet. I like it a lot for target work. I’m not sure if it resists being driven into the rifling less than the SST, and you’re already getting great numbers, so sounds like you have a plan.

[SCJim]

I have always noticed GRT tends to run on the conservative side. I have a feeling that around 30 - 30.5 there is another node but I will still stick with that low node. It gets the job intended for done with less wear and tear on the brass and getting to the target a few milliseconds faster would not make that much difference in regards to the wind. If I were shooting to 1000 that would be different. Thanks for the tips though

[SCJim]

I loaded 10 rounds each at 28.5, 28.6, 28.7, and 28.8. I will shoot them at 100 yards over my chrono to verify that is a flat spot in the curve. The if weather permits load 50 or so to tweak seating depth to see if I can tighten the groups a bit more. For AR Tactical consistent 1 MOA accuracy with 20 round low ES's would be do the trick.

[SCJim]

I was pretty pleased with the velocity spread, but I think the grouping can be improved using a scope with finer crosshairs. The 1 inch red dots were completely cover by the crosshairs. I have a Arken 4 - 16x50 scope with a "christmas tree" reticle along with rings and level is now on order and should be here sometime next week. Still the velocity spread over the a .4 grain spread was only 32FPS over 40 rounds. I would feel very comfortable loading to 28.7 and shooting this load from 32F to 95F. Grouping over the 40 rounds was 2.156 with a 95% CEP of 1.3 MOA. Plenty good enough even with the current scope to compete with. With a finer resolution crosshair I think I can cut at least .3 or more from that. I hope to get the CEP numbers below 1 MOA before competing.

Here is a composite overlay of all 40 rounds exported from the OnTarget program. [ATTACH=CONFIG]19034[/ATTACH]

[Fess]

Has anyone run some of the original Alexander Arms pressure-tested load data through GRT? I remember that the Quickload program at the time (roughly 2006) would predict higher pressures than measured with test barrel. I wonder if GRT will do the same. A couple of sources speculated that the primer would start moving the bullet before the main charge ignited. By the time most of the charge went off, the bullet had moved enough that there was more volume in the case. In a recent Hornady podcast, one of the guests mentioned a similar thing, although he did not mention the Grendel by name. If I remember correctly, some people got better agreement with reality by inputting a slightly larger case volume.

[SCJim]

Has anyone run some of the original Alexander Arms pressure-tested load data through GRT? I remember that the Quickload program at the time (roughly 2006) would predict higher pressures than measured with test barrel. I wonder if GRT will do the same. A couple of sources speculated that the primer would start moving the bullet before the main charge ignited. By the time most of the charge went off, the bullet had moved enough that there was more volume in the case. In a recent Hornady podcast, one of the guests mentioned a similar thing, although he did not mention the Grendel by name. If I remember correctly, some people got better agreement with reality by inputting a slightly larger case volume.

To get the most out of the GRT program you have to go in and tweak all of the variables in relation to your gun and load. I have noticed that GRT does err on the conservative end. On the optimum barrel time screen for instance they predicted node 7 to be at 2424 at 28.16 gns of powder and I ended up at 2450 at 28.5 gns. Still it was close. I think a lot depends on how much input they have on a powder. Still it is a useful tool to compare powders and bullets give you a starting point for load development. I find it more versatile than Quickload but then I started using both programs at about the same time and gravitated toward GRT.

[LRRPF52]

Has anyone run some of the original Alexander Arms pressure-tested load data through GRT? I remember that the Quickload program at the time (roughly 2006) would predict higher pressures than measured with test barrel. I wonder if GRT will do the same. A couple of sources speculated that the primer would start moving the bullet before the main charge ignited. By the time most of the charge went off, the bullet had moved enough that there was more volume in the case. In a recent Hornady podcast, one of the guests mentioned a similar thing, although he did not mention the Grendel by name. If I remember correctly, some people got better agreement with reality by inputting a slightly larger case volume.

It has been done through QL using Hornady, Hodgdon’s, Western Powders, and AA data, as well as cross-referenced with a multitude of known factory loads on a pressure test breech. QL is typically 10,000psi off, meaning the information is invalid, and could be unsafe with the powder/bullet combos that represent loads thousands of PSI lower than they actually are.

We have so much industry pillar (AA, Hodgdon’s, Hornady, Nosler, Sierra, Western, Vihtavuori) pressure-tested data and have had most of it for so long, that I don’t know why anyone would still use inaccurate predictive models.

If you entered all of the known pressure-tested data into a 6.5 Grendel-specific internal ballistics engine and built a model that way, it could be useful. You could even model short/mid-life SAAMI/ long chambers, different rifling profiles, different brass volumes, and primers. That’s going to take a lot of your time and effort, provided the baseline competence is there to conduct a valid modeling.

[grayfox]

Grt is easier for me to use, I will admit.
One tweak I did after reading some was for the grr to use a siebert factor of 0.45. but I also play with the volume, adjusting it in a "calibration" mode for a "known" book load, usually winds up being a higher volume than the list value for MV/pressure to come into line. I figure also (just a theory) that powders and lots vary so for my lot, adjusting the volume to make pressure/MV/charge load more or less agree, is an acceptable tweak to make it useful. I agree it is a fairly useful tool as an estimate. The barrel response to the load is the final judge however.

[SCJim]

We have so much industry pillar (AA, Hodgdon’s, Hornady, Nosler, Sierra, Western, Vihtavuori) pressure-tested data and have had most of it for so long, that I don’t know why anyone would still use inaccurate predictive models.

The first three statements of my OP

A few months back I bought 1000 Lapua 120 gn Scenars specifically for my 6.5 Grendel but never got around to it until a few days ago. Looking through my powder locker I noticed I had several pounds of Leverevolution powder so I decided that would be the powder I would start with. Official sources for 6.5 grendel load data for both the powder and the bullet is scarce as hen's teeth so I had to use internet postings, Quickload, and Gordons Reloading Tool. I personally prefer GRT over Quickload so I decided to use it for the development,but that is purely a personal preference. Bearing that in mind, here is some legalese

CAUTION: The following post includes load data generated by calculation in Gordon Reloading Tool (GRT) software is based on particular powder lots, the assumption the primer is as mild as possible, and assumptions about component, chamber and gun geometry that may not correspond well to what you have. Such data should be approached by working up from published starting loads. USE THIS DATA AT YOUR OWN RISK. Neither the writer, nor GRT's author assumes any liability for any damage or injury resulting from use of this information or information derived from it.

One of the first steps in using any ballistic software is putting all the parameters from your rifle into it. Barrel length, twist, gas port size and location etc come into the equation and can affect the outcome. GRT seems to be on the conservative side but do use common sense and caution and check for overpressure signs at every turn.

I find GRT's output to be reasonably close and a bit on the conservative side on all the predictions IF I take the time to adjust all the variables to my rifles configuration and shooting conditions. Of course if you just use the programs standard data values it will be garbage in/garbage out. I own relatively new versions of Sierra, Hornady, Nosler, and Berger load manuals and have all the powder manufacturers load data sites book marked. Data for Lapua bullets is rare as hens teeth in every cartridge. I still find GRT to be extremely useful and even use it to fine tune load data which I found in the books and on the sites.

While it is not perfect I have yet to find any factory load data that accurately represents and rifle I own so published load data never accurately predicts the velocities either. Most published data will use a 24 inch test barrel for bolt guns. Not a single one of my bolts rifle have a 24 inch barrel. Most are 26 - 30 inches with my bench rifles being on the shorter side. Rarely do the powder manufactures have data for the bullet I am using and the bullet makers may or may not have data for the powder I am using. When developing a load I never rely just on a single source, even when I can find data using the same bullet and powder and I always start at the lowest charge and work my way up shooting over a chronograph while inspecting every piece of brass fired. Closest I ever came to having a issue was using Hodgdon data for the 260 Remington with H4350 and 142 SMK's. I fired exactly 2 rounds before packing up and heading home and double checking everything. Turned out the Hodgdon starting load for the 260 was 2 full grains higher than the maximum load for the 6.5 Creedmoor. The Remington case volume is only a couple of tenths more than the CM. Since that incident when loading for the 260 I always check the data for the CM to make sure they are at least close and other than that one incident they always are.


Just out of curiosity can you name a published source that uses a Lapua 120 gn Scenar, Hodgdon Leverevolution powder, 20 barreled inch Grendel gas gun being shot in 85 - 90 F temps ? No ? How about data for a 30 Grendel with 115 gn bullets and N120? Crickets on that one too? Well that is why I use GRT. While not 100% accurate GRT gives me a good starting point that while may be a tad on the conservative side is a lot better than just pulling a starting point out of thin air.

[LRRPF52]

Lapua data has been available and plentiful for well over a decade for 6.5 Grendel, via Vihtavuori. Lapua and Vihtavuori are sister companies.

They didn’t have the 120gr Scenar-L at the time, but did publish 123gr Scenar data.

Bullets include 100gr FMJ, 100gr Scenar, 108gr Scenar, 120gr Barnes TSX, 123gr Scenar, 139gr Scenar, 140gr Naturalis, 144gr FMJBT, and 156gr Mega

Powders include N130, N133, N140, N530, and N540.

It's included in Volume I of the Grendel Handbooks, along with AA, Hodgdon’s, and Western Powders data.

Here’s Vihtavuori’s 6.5 Grendel Load Data.

The only Scenar-L they added is the 136gr.

[LRRPF52]

Just out of curiosity can you name a published source that uses a Lapua 120 gn Scenar, Hodgdon Leverevolution powder, 20 barreled inch Grendel gas gun being shot in 85 - 90 F temps ? No ? How about data for a 30 Grendel with 115 gn bullets and N120? Crickets on that one too? Well that is why I use GRT. While not 100% accurate GRT gives me a good starting point that while may be a tad on the conservative side is a lot better than just pulling a starting point out of thin air.

I get where you’re coming from. As long as you can tweak the model with a lot of real world data to narrow its predictive functions, and if it accurately accounts for those inputs, I can see it being useful, but how much more useful is that than collecting as much load data from all available sources and crunching it yourself?

The problem with any theoretical internal ballistics program is just that, they have not gone and tested these powder, bullet, case, and primer combinations.

There are loads for 123gr Scenar with LEVERevolution on Ammoguide.

There are published LEVERevolution loads in Volume II of the Grendel Handbooks under the 120gr Nosler Ballistic Tip, 123gr A-MAX, 123gr SST, and 129gr SST.

We didn’t publish anything higher than 31.5gr for the 120 NBT. 120gr NBT isn’t a Scenar-L in terms of jacket material, hardness, or thickness of course, but the numbers are the same for the 123gr Scenar.

I would put 31-31.5gr as your ceiling with LEVERevolution under the 120gr Scenar-L, start 3-5% below that and work up in .3gr increments.

I didn’t see any velocities next to those .1gr increment charge weights you loaded.

If you were going to load .1gr increments (too fine really in my experience to get much useful data from), I would have shot them at 300yds and colored the tips with a marker, or use some way to track each shot placement.

It doesn’t make much sense to go below .2gr with a ~30gr case capacity cartridge. I generally only recommend using .2gr increments when working with the monolithic bullets and 130-140gr, because of how quickly they build pressure.

What did GRT predict with LEVERevolution and 120gr Scenar-L?

[LRRPF52]

Closest I ever came to having a issue was using Hodgdon data for the 260 Remington with H4350 and 142 SMK's. I fired exactly 2 rounds before packing up and heading home and double checking everything. Turned out the Hodgdon starting load for the 260 was 2 full grains higher than the maximum load for the 6.5 Creedmoor. The Remington case volume is only a couple of tenths more than the CM. Since that incident when loading for the 260 I always check the data for the CM to make sure they are at least close and other than that one incident they always are.

I used Quick Load once to predict start loads for .260 Rem using cut-down 120gr GMXs to 95gr, provided by another forum member.

I referenced 95gr V-MAX data, but also took into consideration that the GMX is a monolith, so it would build pressure much faster and resist being driven into the lands, so I backed off of that.

It still blew the primers out. I learned how useful QL was in those situations, which was not much at all. No bullet/powder combo existed for what I was doing, and the predicted numbers were so far off as to be dangerous. I suspect they were over 70,000psi. AR-10 ate it fine, but it was a failed process for sure.

[SCJim]

I used Quick Load once to predict start loads for .260 Rem using cut-down 120gr GMXs to 95gr, provided by another forum member.

I referenced 95gr V-MAX data, but also took into consideration that the GMX is a monolith, so it would build pressure much faster and resist being driven into the lands, so I backed off of that.

It still blew the primers out. I learned how useful QL was in those situations, which was not much at all. No bullet/powder combo existed for what I was doing, and the predicted numbers were so far off as to be dangerous. I suspect they were over 70,000psi. AR-10 ate it fine, but it was a failed process for sure.

every batch of powder can be different. Gordons realizes that and suggests you calibrate program to your rifle and lot of powder early on in development. Did you change the bullet parameters to your altered bullet. Did you start with a minimum charge using published data from a bullet /powder combo that was similar.

Gordons reloading page propellant correction directions https://www.facebook.com/845221829183230...702341307/

Personally I like to find as many sources when I can to establish a starting load. I will spend hours looking on the net and going through all the published load data I can find before ever dropping the first gn of powder into a case. I always start at a minimum charge and even when I am at the end of charge development I will always choose the lowest velocity node that meets my needs in order to minimize barrel wear and use the least amount of powder. When you shoot 300 - 400 centerfire rounds per month and sometimes more every gn of powder counts.

I would never reccomend using either software tool as the only source for load development if at all possible. Even with the Lapua/Leverevolution development which had no official published data I did a search for user recommended loads on this forum and others then ran the number in GRT and started very low and worked my way up in .2 gn loads

I just sat here and loaded in six bullet/powder minimum/maximum from Hodgdon, Sierra, Berger, Barnes, and Nosler and in all six GRT was conservative compared to the published data. Not saying that is the case 100 % since there are 1000's out there. But like I said there are several free sources online and even with the data books a email or phone call asking for a load suggestion from the bullet or powder distributer is all that I have ever needed to find a start point.

[LRRPF52]

I’m the same way with gathering as many sources as possible. The main reasons for that are to obtain different case, primer, powder, and bullet combinations.

The different published load data for other cartridges will almost always have different cases and primers being used, so you can build your own library of sorts.

I’ll even acquire different year prints/editions to add to my library. More data = more informed loading possibilities.

If you’re wild-catting, you need to have a higher level of understanding of propellant densities and burn rates that will be appropriate for your case shape, neck/shoulder geometry, bullet diameter/mass, and bore volume relative to all of that.

What is GRT estimating for those different charge weights under the 120gr Scenar-L, specifically up to the 31.5gr LEVERevolution load?

[SCJim]

What is GRT estimating for those different charge weights under the 120gr Scenar-L, specifically up to the 31.5gr LEVERevolution load?

GRT flags 31.5 gns as overpressure @63,578 PSI and 2718 FPS. Using the propellant mass calculation function of GRT it came up with 30.29 gns to produce 2600 FPS and flagged it as a dangerous load @ 54817 PSI. GRT flags anything at Pmax absolute - 15% as dangerous. This was using velocity data from my rifle and current load workup to calibrate program and powder values. The reason I mention this is I use my chronograph as a indicator of over pressure, I find it much more reliable than primers and case head marks because of the different hardness of the brass used in different manufactures cases, firing pin hole sizes etc.

Hodgdon's fastest FPS for 120 gn bullets is listed is with H335 @ 2508 with a 24 inch test barrel

Sierra goes a bit farther @ 2600 FPS using power Pro Varmint

Berger has maximums for several powders up to the 2570's

Hornady stops @ 2500 FPS with CFE 223

When developing a load and I reach what I think is max FPS for that bullet and cartridge I stop regardless of the charge. Since I took up long range shooting I have seen two people destroy custom rifles trying to get that last few FPS. Luckily both walked away with their hands and face and no bystanders were injured in either incident. Although I am sure both had to trash their underpants afterwards. One gave up shooting entirely and sold all his gear and took up golf, no kidding. He was a a damn good LR shooter too, always in the top 2 or 3 at matches

[SCJim]

Update

Installed the new 4-16 Arken scope and made it back to the range, kind of windy with a storm rolling in but then that is the best conditions for practice.. As I suspected the thick crosshairs on the Sig Sauer were what were holding me back, after the initial shot I made 2 scope adjustments to get it close to zero. Then I installed the Magnetospeed and shot a 10 shot group which measured just at 1 inch at 100 yards. I the took it out to 850 yards and put 20 more shots on a 18 inch steel plate with 5 to 10 mph crosswinds. This will make a great 600 yard load but I need to find a higher node for 800 yards, At 28.8 gns of Lvr and 2325 FPS at 82F it does not have quite enough speed to trip the electronic target past 700 yards. Anyway I am quite happy with this rifle and load for 100 - 600 yards.

[ATTACH=CONFIG]19087[/ATTACH]

[Serenitynow]

Update

Installed the new 4-16 Arken scope and made it back to the range, kind of windy with a storm rolling in but then that is the best conditions for practice.. As I suspected the thick crosshairs on the Sig Sauer were what were holding me back, after the initial shot I made 2 scope adjustments to get it close to zero. Then I installed the Magnetospeed and shot a 10 shot group which measured just at 1 inch at 100 yards. I the took it out to 850 yards and put 20 more shots on a 18 inch steel plate with 5 to 10 mph crosswinds. This will make a great 600 yard load but I need to find a higher node for 800 yards, At 28.8 gns of Lvr and 2325 FPS at 82F it does not have quite enough speed to trip the electronic target past 700 yards. Anyway I am quite happy with this rifle and load for 100 - 600 yards.

[ATTACH=CONFIG]19087[/ATTACH]

What specific Sig and Arken scopes are you referencing in this thread ?
I have a Vortex 3-9, but am looking for more magnification for longer range shooting. My eyes ain't what they used to be.