SRP Vs LRP for 6.5CM

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SRP Vs LRP for 6.5CM

Post by JimTom » 21 May 2018, 12:03 pm

G'day gents.

Just after some information from someone who is better informed than I on whether their is any advantage in using small rifle primer brass over the large rifle primer brass when reloading the 6.5CM. As I understand it, the SRP will allow reloading to higher pressure, and possible better accuracy?
I am thinking their must be some merit in it as Lapua have the .308 Palma brass which has a SRP.
I see the reloading data on the ADI website for 6.5CM is published for use with Federal large rifle 210M primers.
If one were to reload using the small rifle primer, is the published reloading data for large rifle primer still valid?
Any input appreciated.

Thanks.
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Re: SRP Vs LRP for 6.5CM

Post by sungazer » 21 May 2018, 1:33 pm

All the data published is just as valid for SR primers and LR primers no difference. You still can not go over the max powder pressure limits. The Brass may last longer and may give you a lower SD. The real difference is in the size of the flash hole the SR1.5mm LR 1.8mm. I have found a slightly faster 20fps using Large Primers. I have nearly all SR primers in 308 and all in 6.5. The 6.5 being smaller in size so it should benefit more than the 308 is my thinking.
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Re: SRP Vs LRP for 6.5CM

Post by Flyer » 21 May 2018, 2:15 pm

Good question. I haven't started load development yet, but what I did notice when I started collecting load data is that I saw a lot of 2209 (H4350) loads around 42.5-43.5gr and even over 44gr with 140-142gr projectiles. ADI lists its maximum as 41.5 for the Sierra 142 SMK (and 40.0 for the 140gr Hornady A-Max), while Sierra lists 41.9 (142 SMK) and 42.0 (140 SMK).

Most of the loads I collected were with large primers.

To put things into perspective, the small primer brass - Lapua - has a smaller case volume than just about all other 6.5CM brass, so it will spike more pressure for the same load - at least in theory.

The moral of the story is you're going to have to work your load up. But I did come across a couple of interesting videos that show the difference between the small primer Lapua brass and large primer Hornady brass using the same load (41.3gr 2209/H4350 and 140gr Hornady ELD-M).

The small primer brass was not only 20-30fps faster, it was more accurate. The video maker did say it was colder on the day he tested the large primer brass, so that may have accounted for the lower velocity.

Small primer 6.5CM review: https://www.youtube.com/watch?v=ZPu0DzIgKNk

Large Primer 6.5CM review: https://www.youtube.com/watch?v=ypI6D-i57uk

The real advantage to using small primer brass is brass life, as small primer pockets stay tighter longer. There's another video where they got 20+ reloads from a single Lapua small primer 6.5CM case.

Personally, I'll be using small primer brass for my target shooting - as the cases will get many reloads - but I'll probably also work up a hunting load using once-fired large primer (cheap Federal 140gr ammo at $29 a box) brass so I don't have to worry about losing it out in the field.

I guess it really depends what you want to do with your loads - what sort of accuracy you're looking for - and how often you think you'll be reloading them. The Lappy brass isn't cheap - especially in 6.5CM - and is anywhere from $180-$200+ per 100.
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Re: SRP Vs LRP for 6.5CM

Post by Flyer » 21 May 2018, 2:22 pm

There's an excellent video on the difference between 6.5CM loading dies, too, here: https://www.youtube.com/watch?v=9I2pwRDxDOQ

Bottom line, avoid the Lee dies!
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Re: SRP Vs LRP for 6.5CM

Post by JimTom » 21 May 2018, 2:47 pm

Flyer wrote:There's an excellent video on the difference between 6.5CM loading dies, too, here: https://www.youtube.com/watch?v=9I2pwRDxDOQ

Bottom line, avoid the Lee dies!


Thanks mate. I am currently using Lee dies for my 223 and 308, and getting great accuracy from my reloads. The more I read and hear though it seems that Lee aren’t the way to go at all. Think I will get Redding dies for the 6.5 and eventually change my other dies over as well. Have had several people tell me that Lee are no good.
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Re: SRP Vs LRP for 6.5CM

Post by Flyer » 21 May 2018, 3:07 pm

It's all a matter of perspective and how much money you want to spend for incremental improvements in accuracy. I guess if you're spending thousands on a benchrest rifle, then a few extra $ here and there for reloading equipment is worth it. If you only want to hit something when you hunt, then it's probably not worth it.
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Re: SRP Vs LRP for 6.5CM

Post by JimTom » 21 May 2018, 7:14 pm

Flyer wrote:It's all a matter of perspective and how much money you want to spend for incremental improvements in accuracy. I guess if you're spending thousands on a benchrest rifle, then a few extra $ here and there for reloading equipment is worth it. If you only want to hit something when you hunt, then it's probably not worth it.


Mate I do a bit of shooting at the range but not competition, and my rifles are run of the mill hunters.
I don't think I would be good enough to notice the difference in accuracy produced by different dies.
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Re: SRP Vs LRP for 6.5CM

Post by SCJ429 » 21 May 2018, 9:01 pm

308 shooters have used small primer Palma brass and the jury is out regarding any accuracy advantage. As Flyer said the amount of brass around the primer pocket prevents enlarged pockets and loose primers. If you shoot CCI use BR4 primers or Magnums with your Lapua brass. I must say I do not have any experience with the calibers but do use BR4 in all my 6, 7 and 30 BR cases.
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Re: SRP Vs LRP for 6.5CM

Post by sungazer » 21 May 2018, 9:40 pm

Dont use the Magnums it is really not needed esp in a 6.5 C case. The SR with the 1.5mm flash hole is good for a 308 which has a longer column of powder but the exact same case. So a shorter column of powder will ignite just fine with the SR primer but use the BR4 for just a few $ more they are better.
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Re: SRP Vs LRP for 6.5CM

Post by JimTom » 22 May 2018, 6:09 am

sungazer wrote:Dont use the Magnums it is really not needed esp in a 6.5 C case. The SR with the 1.5mm flash hole is good for a 308 which has a longer column of powder but the exact same case. So a shorter column of powder will ignite just fine with the SR primer but use the BR4 for just a few $ more they are better.




Thanks for the tip mate. Given the input I have recieved here I think I'll get the SR primer brass and try the BR4.
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Re: SRP Vs LRP for 6.5CM

Post by SCJ429 » 22 May 2018, 7:47 am

That is interesting Sungazer, most competition shooters with a 6.5 use CCI BR4 or 450. You would think if there was no need they wouldn't do it. My understanding was that you get more consistent ignition and they have harder, thicker, cups, which allows higher pressure.

30 BR shooters in score competition use 450s and the powder column is almost half the height of a 308.
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Re: SRP Vs LRP for 6.5CM

Post by Cooper » 22 May 2018, 8:02 am

I am using Lapua brass with the Small rifle primer. I am just using standard Sellior and Bellot small rifle primers. But also have CCI450 small rifle magnum primers. I don't think it is important that the magnum primers are hotter. But the magnum primers handle pressure better as they have thicker cups. I had to back my charge off with the Lapua brass a couple of grains compared to Hornady brass.
I am running 38.9gr AR2209 with 143 Eld-X for 2700fps (26 inch barrel Howa)

I started with the Lee dies. Need turn down decapping pin for Lapua brass as it also has small flash hole. I have up upgraded to Forester should bump die with 289 bushing. I am actually going to try the Lee die again to see if it effects accuracy.
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Re: SRP Vs LRP for 6.5CM

Post by sungazer » 22 May 2018, 8:16 am

SCJ429 Thats exactly what I was recommending the SR with the BR4. Thats my experience as well as in thats what most competition shooters use, although there is a lot of copy one and other in that game.
However I have done my own tests over the chrono with the same brass same primer and different size flash hole and found the standard SR flash hole gave the best results.
Cooper the BR4 and even the CCI standard have the same thicker cup as the magnum primers so no problem there. There are more problems in factory guns where the firing pin to bolt hole is a little larger tolerance and that is when you get the cratering effect when primer flows back around the firing pin. I get this in my Rem 700 when I use the same loads as in my Barnard action that just leaves the tiniest dent in the primer. The chamber in the two barrels are exactly the same, same reamer, same Gunsmith same week made.
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Re: SRP Vs LRP for 6.5CM

Post by Flyer » 22 May 2018, 3:23 pm

So by standard flash hole size, do you mean 1.5mm (.059")? Nearly all my .223 brass has 2mm flash holes with the small primers. The ones that didn't (early ADI and some current OSA head stamps had/have .062"), I drilled out to 2mm to standardise.

I was thinking of opening up my Lappy brass to 2mm. Did you see a big difference in accuracy/velocity/spread etc? I have a Lee decapper and some Forster FLS dies on the way.
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Re: SRP Vs LRP for 6.5CM

Post by Gaznazdiak » 22 May 2018, 3:52 pm

JimTom wrote:
Flyer wrote:There's an excellent video on the difference between 6.5CM loading dies, too, here: https://www.youtube.com/watch?v=9I2pwRDxDOQ

Bottom line, avoid the Lee dies!


Thanks mate. I am currently using Lee dies for my 223 and 308, and getting great accuracy from my reloads. The more I read and hear though it seems that Lee aren’t the way to go at all. Think I will get Redding dies for the 6.5 and eventually change my other dies over as well. Have had several people tell me that Lee are no good.


Hi JT,
Not being a smart-arse just asking, I'm a hand rolling newbie and I too successfully use Lee dies, so "if it ain't broke, why fix it?"
I had quite a few people tell me the Lee powder scale was a fine and accurate piece of kit, yet I find it such an utter fiddly bastard that it never gets used.
If you're getting satisfying accuracy with them, like the old Mortein ad said, "when you're on a good thing, stick to it".
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Re: SRP Vs LRP for 6.5CM

Post by JimTom » 22 May 2018, 4:02 pm

Gaznazdiak wrote:
JimTom wrote:
Flyer wrote:There's an excellent video on the difference between 6.5CM loading dies, too, here: https://www.youtube.com/watch?v=9I2pwRDxDOQ

Bottom line, avoid the Lee dies!


Thanks mate. I am currently using Lee dies for my 223 and 308, and getting great accuracy from my reloads. The more I read and hear though it seems that Lee aren’t the way to go at all. Think I will get Redding dies for the 6.5 and eventually change my other dies over as well. Have had several people tell me that Lee are no good.


Hi JT,
Not being a smart-arse just asking, I'm a hand rolling newbie and I too successfully use Lee dies, so "if it ain't broke, why fix it?"
I had quite a few people tell me the Lee powder scale was a fine and accurate piece of kit, yet I find it such an utter fiddly bastard that it never gets used.
If you're getting satisfying accuracy with them, like the old Mortein ad said, "when you're on a good thing, stick to it".



Good point mate.
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Re: SRP Vs LRP for 6.5CM

Post by sungazer » 22 May 2018, 5:26 pm

The 223 cases with the SR are a different case in both sense of the word. They use the SR just because of the size of the case however use really a larger than standard flash hole as you have seen 2mm in a 308 case the standard large flash hole is 1.8mm. There is some new brass called Alpha that is going to arrive in Australia soon that will have a small primer but again a 2mm Flash hole. This brass is made in the US and I think from reading about it is "Tuned" for very cold weather. Like below freezing. Its not something we really have to worry about here in Aus. I found that as the flash hole size increased so did the velocity and also the ES and SD. I think those results are in line with people that have tried the magnum primers in a 308. Its just not needed and in fact causes a less consistent powder burn. Consistency is the key to shooting well. If it goes 200fps slower but the same speed every time you will see it in the results. As opposed to faster but an ES of 60 fps.
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Re: SRP Vs LRP for 6.5CM

Post by JimTom » 22 May 2018, 5:37 pm

Have managed to find some well priced 6.5 CM Lapua brass ($145/100) with small rifle primer. Thanks everyone for the input.
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Re: SRP Vs LRP for 6.5CM

Post by Cooper » 22 May 2018, 6:52 pm

JimTom wrote:Have managed to find some well priced 6.5 CM Lapua brass ($145/100) with small rifle primer. Thanks everyone for the input.


That's cheap! I think paid $185. But I think the Lapua brass is worth it.
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Re: SRP Vs LRP for 6.5CM

Post by JimTom » 22 May 2018, 7:02 pm

Yes mate I think $145 is a good price. Have seen it up to $195.
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Re: SRP Vs LRP for 6.5CM

Post by SCJ429 » 22 May 2018, 7:25 pm

Thanks Sungazer, I am finding there thread very informative. My general practice is to try magnum primers in heavy for caliber projectiles using slower powders. For me a 140 grain 6.5mm using 2209 is a good candidate. My understanding was that CCI400 uses a 0.020 thick cup and the BR4 and 450 use a 0.025 thick cup. A high pressure cartridge like the 6.5 Lapua or CM really needs the thicker cup to prevent pierced primers. I also get less vertical and an extra 40 fps when I use the 250 in a 6.5x55 Swedish. Have you experienced any primer issues when you use CCI 400?
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Re: SRP Vs LRP for 6.5CM

Post by sungazer » 22 May 2018, 9:09 pm

i think I have only used 1 box of 100 of CCI 400 as compared to 1000's of BR4 as when something is working well don't change. They are a little more expensive but not in the scheme of things. But to answer your question so far I have never had any issues with primers. I think I pushed a little hard a week or two back on a load so I now that guns limit with that load. That was in a Rem 700 and the bolt allows more damage to the primer.
I have and am still trialing loads for my 6.5C using Lapua Brass and BR4 primers. I initially went for the 140grn projectile and have had some good results but the info I have got from other shooters in the know say the 123-130 range is potentially better. Still early days for me with that gun. so far I have been using AR2206H as well and as you say I think 2209 will be a better powder. It will take me some time as I have other shooting commitments. Also other guns that are well known ballistic and shooting wise for other duties. I can see the 6.5C taking over that work horse duty when I get it sorted and confidence built up.
I understand what you mean about slow powders and the use of magnum powders but 2 things 1)The 6.5 has a pretty short column of powder and 2209 is not that slow. 2) The guys shooting 7mm RSAUM use 2213c a slower powder and a longer case and still get better results not using a magnum primer.
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Re: SRP Vs LRP for 6.5CM

Post by SCJ429 » 22 May 2018, 11:01 pm

I understand your reasoning that the BR4 work well for you, as they do for me. I had a quick look at the Precision Rifle Blog who report on PRS shooting in the US. The 6.5 Lap and CM are used widely by these guy and they reported on the equipment list for the top 50 for last year. 14 shooters in that group used CCI 450 and seven used BR4. None of these guys are using Retumbo so I assume they are getting great results over and above the BR4 in their competition rifles chambered in 6mm or 6.5mm cases using something around the burn rate of Varget. If I was to start a load for a 6.5 CM, my current experience is zero with this cartridge, I would use a 140 Berger hybrid with some 2209 and a CCI 450 and see how it shoots. That is not to say you wouldn't outshoot me using 2206 and BR4, I would love to know if someone has tried and what they found.
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Re: SRP Vs LRP for 6.5CM

Post by sungazer » 23 May 2018, 8:47 am

I wrote to the accurate shooter website / 6mmBR website guys giving them a little feedback and also commented on their lack of 6.5C articles load data, cartridge reviews ect. What I did get back was another opinion on to try the 130 grn range projectiles as well. I first started developing a load for the Berger 140 VLD, I have since and also had the Lapua 143 Scenars, and the 123 lapua Scenars both used a lot in F class in all the 6.5mm configurations. I have a box of Sierra 140 ? and a box of the Hornady 143 ELD-X still to have a play. So I can put up some results if your interested. I start by putting them over the Chrono and getting a speed I am after at a depth I think they will work at look for any really bad groups that would disqualify that load then do a seating adjustment to see in I can improve on the group. Sometime this all get delays and i just load up some and give them a quick try find they are acceptable and go shooting. I bought 2209 specifically for this cartridge but already had 2206H so just started with it. It works Ok I shot a 56.2 using some load development rounds ie 5 0.3 gr apart at 600yrd using a Howa 1500 X size was 148mm and y was 250mm that was just the max between two outliers the other 8 would have been in the 150mm vertical y as well. That was with the 140 Berger VLD.34.0 grn 34.3 grn AR2206H
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Re: SRP Vs LRP for 6.5CM

Post by SCJ429 » 23 May 2018, 8:06 pm

Thank Sungazer, I would be very interested in your results and the speed you are able to get. What sort of barrel are you using and how long is it?
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Re: SRP Vs LRP for 6.5CM

Post by Flyer » 23 May 2018, 8:24 pm

Good write-up on Starline 6.5 small primer 6.5CM brass here: https://www.ocabj.net/starline-brass-6- ... ss-review/

Unlike Lapua, they have standard .080" flash holes, so no issue with decapping. Cheap brass - not as good as Lappy - but the bloke in the above article got them to shoot OK.
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Re: SRP Vs LRP for 6.5CM

Post by sungazer » 23 May 2018, 8:48 pm

It is a Howa 1500 Stock standard just put in a chassis.It is a 26 inch Varmint profile barrel. I will let you know how it goes. I seem to have got it on special and perhaps a limited qty as I see none of the same advertised ATM.

Flyer I just read that article and I think it pretty clearly states that the Starline is not of the same quality as the Lapua. also mentions about the larger flash hole problems with the ES more pressure signs ect.
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Re: SRP Vs LRP for 6.5CM

Post by Flyer » 23 May 2018, 9:46 pm

Yep, I did mention that ;)

I just put it up for anyone interested. He also says at the end of the article that he did get some pretty good groups with it, so it's not too bad.
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