7mm Allen Magnum/RL33/180 gr Berger testing

[Fiftydriver]

After seeing how well RL33 performed in my 338 Allen Xpress, I was very excited to see how it would perform in my 7mm Allen Magnum which is also based on the 338 Lapua parent case. From everything I have been seeing, RL33 is producing 90 to 150 fps over what Retumbo has been producing in same chamberings.

Wanted to see how ol' Green would do with the 180 gr Berger Hybrid Hunter and this new powder. To get a better idea of pressures generated to compare it to my Retumbo load I formed up a new batch of 7mm Allen Magnum brass.

Out of old green (26" barrel length) with its Rem 700 receiver, I do not push things overly hard. My standard load for the past 4 seasons have been 95.0 gr Retumbo under the 160 gr Accubond which gives an average velocity of 3414 fps. This load just starts to show some slight primer cratering around the firing pin divet. This is more to do with the large diameter Rem firing pin then anything but its a good place to stop. I developed this load with Retumbo adding one grain at a time at 75 degrees and stopped when I went from no cratering at all on the primer divet to just slight cratering with 1.0 gr increase in powder charge and stopped there. This is simply because I do not want to push the Rem 700 to hard.

So, I wanted to see what the new berger bullet would do with this powder, even if it does not shoot well in this long in the tooth barrel, at least I can get some good velocity testing. I started at 93.0 gr and worked up from there with the freshly formed new Lapua brass.

93.0 gr.....................3065 fps Extremely low pressure, increase 2 grains
95.0 gr.....................3152 fps
97.0 gr.....................3244 fps
98.0 gr.....................3270 fps
99.0 gr.....................3308 fps
100.0 gr...................3329 fps No primer divet cratering at all
101.0 gr...................3358 fps Very light primer divet cratering Working load for old green.

So with what appears to be very similar chamber pressures, it takes 6 grains more RL33 to get a 20 gr heavier bullet within 60 fps of my standard 160 gr Accubond load. Now figuring the BC advantage of the Berger bullet, this will be a dramatic improvement in down range ballistic performance.

Again, this is in a Rem 700 based rifle so I do not push things hard at all. When I get a chance I will test this new powder in one of my Raptor Stalker (27" barrel) or Raptor LRSS (30" barrel) and develop loads using Norma brass to find the pressure limits of this powder and bullet combo.

With Retumbo, I have already tested the 160 gr Accubond in one of my Raptor LRSS and it was easy to top 3500 fps. In fact, using the Norma brass, Top loads in those testes topped out at an average of 3540 fps and primer pockets held up to 5-6 firings. Using Lapua brass, there was ZERO sign of any pressure issues at all and primer pockets never loosened up.

Using that as a reference and seeing what LR33 had done so far, I would predict that the 180 gr berger Hybrid Hunter could in theory be driven to very close to 3500 fps out of my Raptor LRSS rifles and likely 3450 fps in my Raptor Stalkers. Again, theory but will be proving very soon.

So far I have been very impressed with RL33. In everything tested so far, it has shown 90 to 150 fps more velocity with what appears to be identical chamber pressures. STill have to see how it does as far as temp sensitivity. I have heard for years how terrible the RL powders are with temp changes. Personally, I have never really seen that. Now, if you load your ammo to max pressures in cooler temps and then wonder why your seeing pressure signs when its 80-90 degrees out, well, we need to be smarter then that and I know most everyone on here certainly is.

Simple fix, develop your loads when its hot, rechrono when cool and record your velocity. No worries about excessive pressures. I have heard mixed results about RL33. Some have said its extremely stable, close to on par with the Hodgdon powders. A few have said it is terrible but many of them seem to have something against anything except their preferred powders so until we get more widespread data, its a wide open topic in my opinion.

Having worked with surplus ball powders for many years and dealing with their temp issues, I guarantee RL33 is far better then any of those powders over wide temp changes so to me, its really a moot and relatively unimportant point. Many ways to cross that bridge with little fuss.

Anyway, going to do some testing with the 160 gr Accubond as well to get an apples to apples comparision using RL33. I suspect that 3500 fps will be easily attainable in ol' green with this new powder.

More to come.

 

[yama49]

Look foward to more testing.. I have some rl33 to try when my raptor stalker arrives
Was looking at shooting that 195 berger, but looks like i might have to start with another bullet

 

[Kiwi Greg]

Good to see RL33 is working for you Kirby

 

[Fiftydriver]

Look foward to more testing.. I have some rl33 to try when my raptor stalker arrives
Was looking at shooting that 195 berger, but looks like i might have to start with another bullet

I think when the 195 gets here, RL33 will be amazing with that bullet weight. In my Rem 700 based 7mm AM, I am at around 95-96% load density with my 101.0 gr load. I suspect that in a Raptor based rifle or any other full custom rifle, you could load RL33 to 100% load density pretty easily and then some possibly.

With the 195 gr bullet weight, it appears that you would top out right at 100% load density right when you top out in pressures, could not be a better match on paper. Time will tell.

 

[Fiftydriver]

Good to see RL33 is working for you Kirby

I have not been disappointed yet with any test I have done with it but still a lot of testing to do, namely all around use during big game season ranging from pronghorn hunting when it can be upwards of 80+ degrees F to late season whitetail hunting where it can be down to 0 F.

Time will tell but it certainly is showing good results so far.

 

[Fiftydriver]

Today was able to test apples to apples using RL33 with the 160 gr Accubond in my old 7mm Allen Magnum.

As stated previously, my standard load with this rifle is the 160 gr Accubond over 95.0 gr Retumbo with a 3.650" OAL, Fed-215 primer for an average velocity of 3414 fps.

So, I started with RL33 at 99.0 gr simply because with the 180 gr Berger I topped out at 101.0 gr with no real pressure signs. I was a bit surprised at the results.

99.0 gr.........................3448 fps
100.0 gr.......................3477 fps No primer cratering all
101.0 gr.......................3502 fps First sign of very slight cratering
102.0 gr.......................3529 fps

No other pressure signs were present at all even at 102.0 gr but I decided that 101.0 gr would be the correct top working load with this rifle/load combo. Looks like with the 160 gr Accubond, producing the same pressure can be driven roughly 80-85 fps faster using RL33 then with Retumbo. In past tests, this is on the lower end of velocity improvements with this powder.

It appears that RL33 does better with a slightly heavier bullet weight as far as velocity gains but in the 7mm AM, it certainly offers a sizable boost in velocity in both the 160 gr Accubond and 180 gr Hybrid Hunter from berger.

I decided to load up 15 rounds of test ammo using the 180 gr Berger and see if they would even survive the launch out of this very old barrel for some accuracy testing. Tested them at 100, 890 and 1030 yards and I was actually impressed with the accuracy of these bullets at every range. There was no group fired at 890 and 1030 that was over 1 moa in size. And I intentionally heated the barrel up to see if the bullet could handle a hot barrel. They did just fine.

Now, back to the 160 gr accubond. I have not been able to break 3500 fps with this bullet unless using a 30" barrel length in my 7mm Allen Magnum. Now, that is clearly possible with a 26" barrel length using RL33.

Looking out to a 30" barreled Raptor LRSS...... I would be amazed if 3600 fps would not be fully practical with the 160 gr Accubond and close to 3500 fps with the 180 gr Berger. These are only predictions and need to be proven but I would be amazed if these velocity goals were not easily attainable.

More to come. I believe my old 7mm AM will be loaded with the 180 gr berger to roughly 3350 fps for this coming big game season. We will see what happens with pronghorn and big game season.

 

[Korhil78]

Being that your 7 AM is based off of the 338 lapua case, do you think that the 338 LM with a 300 gr Berger would see better results with RL33 than H1000? I probably won't change my load right now as I shot a 4.8" 4 shot group and a 4.9" 4 shot group on two different days out at 1300 yards with H1000 but reloaders love to tinker with new things! I havn't seen a lot of information on RL33 accept what you have been doing so it is cool to read about it.

 

[MMERSS]

Thanks for the info. It will be interesting to get some hard data on temp sensitivity...especially since I have a new jug sitting on the reloading bench.

Thanks for the tests.

 

[jimbires]

I've played with RL17 in a 24" 7-08 . I'm getting 3080 fps with a 140 berger , no pressure signs and good brass life . RL33 is supposedly using the same technology as RL 17 . I expect it will also be a good powder for increasing velocity . I've just bought a 8 pound jug of RL33 and some 300 gr accubonds for a new 30" 338 lapua . I'm still waiting on a few things before I can get shooting this rifle , so I have no data to share . thanks for sharing your info . BTW , I don't seem to have the temp sensitivity issue with RL17 or RL22 that I always read about . Jim

 

[mark fox]

kirby, this is mark fox from " Bad *** GunWorks " i have a cartrage simular to you 7mm allen mag same parent case. shoulder moved foward .110 foward then ultra improved 42 deg shoulder wc 872 volume of 123.3 gr. 190 matrix at at 3345 fps avrage 7 fps dev. .300 " 5 shot at 100 yards. I would like your advice on somthing. wc 872 powder is to slow on the 32" pac.nor pipe. No velocity change beyond 103.0 grains to 107.0 gr. same velocity avrage recorded. using reloader 33 preasure shows up at 104.0 gr. 3312 fps. to fast. i need somthing betweed rl33 and wc872 there is no good source for slow burn rate charts. they all say somthing diffrent. Any ideas on what to try. shooting for 3400 fps with 190 matrix or 3375 fps. berger 195 hY. thanks Mark fox 503-267-4311

 

[Fiftydriver]

Mark,

When I designed my 7mm AM, I played with designs nearly exactly like yours, moved my shoulder forward 100 thou, did not go that extreme on shoulder angle because I have seen some serious issues with these extremely sharp shoulders with powder bridging and as the cases get older, they can get a bit finicky with shoulder collapse when bumping the shoulder.

Also found that there was no increase in performance over my design so kept it as is.

Anyway, I am a bit surpised your not seeing more velocity. My 7mm AM in my Raptor rifles is easily pushing the 190 matrix to 3400 fps in 30" barrel lengths. My personal light Raptor T-Hunter will push them to 3350 fps and it only has a 27" barrel length. These are using RL33.

If your looking for a powder between RL33 and WC872, you may want to try US869 from Hodgdon. I have found its a bit faster burning then most lots of WC872 but lots of WC872 can vary ALOT depending on what you get. I have seen it noticeably slower then US869 and some lots nearly identical so just depends on what you have for burn rate. Guess that's what we get with the lower price.

Not sure if it will work and you WILL notice velocity variation shooting in different temps with all of these ball powders. Sometimes DRAMATIC variation with a chambering like this.

Your pressure issues with RL33 may be your shoulder angle. Hard to say but I am surprised you can not get more velocity with your barrel length.

H-50BMG would probably be ideal in burn rate for your application but unfortunately, this powder is so bulky, I would say you have zero chance to get up to top working pressures and I would suspect powder bridging would be a serious problem.

Good luck!!

 

[mark fox]

I statred this project about 10 years ago my 1st design was just like yours. but with a 42 deg shoulder 32" pipe 180 bergers were 3475 to 3500 fps with w872 100% 103.0 gr no preasure. my first reamer had a .012 body taper. I then moved the shoulder foward and did a .008 body taper and went the 42 deg. shoulder again. Most of my cartrages have .008 or less body taper 40 to 42 deg shoulder. It has worked very well for me. the only down side to it is chambers must be perfect & highly polished. Case preasure desplacement and a more localized burn were my reasons. it has worked very well for me in the past. my 6.5 perseus pushes a 140 gr vld at 3785 with a 34" pipe. 160 matrix at 3592 fps. my 6.5 taz same design off wsm case 140 vld 3495 fps with 28" pipe 73.9 gs of magpro my 8mm kronos custom 265 gr bullets (b.c. .776 bc.) 3471 fps 34" pipe 139.5 gr of retembo. and the list goes on a total of 21 cartrages. We all do things that sometimes it only makes sence to us. we live & learn. my 284 tyrannos will find it sweet spot. just need the write combo. Accuracy has never been the issue. I use to shoot ftr open ( high master) now i just build them. 13 of my guns were at sw berger nationals. I gained high master with my 6.5 perseus. have you ever used vv 570 powder i think i will try it along with the us 869 thanks mark fox 503-267-4311

 

[mark fox]

p.s. Kirby most of my custom cartrages are not for sale and will never be owned by anyone but me and those on my ftr team. The navy and 3 contractors do use the 6.5 ares and the 10mm crebrus. So those of you who were thinking dont ask. see kirby for your super performance needs.

 

[Fiftydriver]

I have found burn rate of VV570 and RL33 to be extremely similar but I have also found that VV570 has a higher burn temp and is harder on throat life then RL33.

RL33 seems to be very sensitive to bullet positioning in relationship to the lands. Seat ogive within 10 thou of the lands and you get very consistent muzzle velocities. Seat much off the lands and you can see some very wide velocity spreads.

VV570 does not seem to be effected as much by ogive to land relationship.

RL33 also seems to be a bit dirty until you get up to its upper range of working pressures but loaded to top pressures. similar to other stick powders.

US869 is also a powder that likes to be loaded to its top pressures, like most of the other ultra slow burning ball powders, keep it in the upper 5% of its pressure range and burns relatively clean for a ball powder. Under that and like WC872, you will need to really stay on top of the carbon build up.