Energy and load

[heritage5]

Hi all
Have been trying to find a starting load for my new 6.5/7mm and was looking at 7saum data I have noticed that a lot of people's loads are over 3500lbs , are shooters keeping under this or just close or not worrying at all.

Guy

[shadow]

How did you come to this conclusion,
Have you got a personal dopler radar,
If so , I havnt seen you measuring everyone's muzzle verlocity
and pulling there ammo apart to weigh projectiles
Ore did you just make a assumption that people are !
Assumptions are like opinions, everyone got one.
You will find the 6.5 -7 prs does best about 2780 with 180grn
on the powders we have over the counter here, cheers

[heritage5]

No not assumptions put the projectile weight and stated velocity in to a bullet energy calculator and you will get the answers eg 180gr @2960= 3502.

[RDavies]

Pretty much everyone I know who is shooting a SAUM is shooting 180s around 2940-2960 Max and 183s @ 2930-2940 regardless of whether they are on a low energy range or not. It just works out that this is as fast as most SAUMs will shoot well, but I expect a 7mm/6.5PRC will be over pressure to get to these speeds.

[heritage5]

Thanks Rod that's what I thought, I can easily get 3050 with no pressure with a 180 hbt 58.5 2213 gives 2930 2940 but still have a little to much vertical anyway working on that. Thanks.

[RDavies]

Thanks Rod that's what I thought, I can easily get 3050 with no pressure with a 180 hbt 58.5 2213 gives 2930 2940 but still have a little to much vertical anyway working on that. Thanks.

It sounds like you have one super fast barrel and would still be pushing pressures.

[shadow]

You stated that they are over the energy limits,
So you asumened we are over,
Whit out you, pulling everyone's ammo and verification of
verlocity, you are assuming we are,
So your assumption is wrong, we are not over.

[heritage5]

No no assumptions only a question and statment of observation The 3500lb limit is range pacific, and as I said the projectile weight and stated velocity on SOME posts are over that limit, anyway the question has been answered.

[PeteFox]

You stated that they are over the energy limits,
So you asumened we are over,
Whit out you, pulling everyone's ammo and verification of
verlocity, you are assuming we are,
So your assumption is wrong, we are not over.

If you're not going to use velocity and projectile weight to calculate muzzle energy, what other genius way are you going to do it?

How do you verify velocity by "pulling everyone's ammo"? A parallel universe

[shadow]

Don't understand your comment, I never said not to use verlocity.
Pull ammo , weigh projectile , shoot ammo over labradar.
How else can you do it , you tell me, not what they say but measure it.
He stated , I have noticed a lot of people, so all I'm saying is
that all I know are under, so dont know how you get most
are over, without testing other persons ammo in real time ,
not what they or he or she said on the net or where ever,
I'm saying the opposite , most are under the limit,
So again without proof , it's just a assumption,
And if your attacking me , then you mite be one of the most that are over,
Personally I don't give a shit if people are over , as long as we
can all shoot and have , thats what it's all about , end of my rant

[BATattack]

No no assumptions only a question and statment of observation The 3500lb limit is range pacific, and as I said the projectile weight and stated velocity on SOME posts are over that limit, anyway the question has been answered.

Dunno. . . .this seems pretty clear to me? He is referencing velocities that have been posted by those doing load development etc. Not really making assumptions by eyeball at the range.

"Stated velocity on SOME posts are over the limit"

[Drop shot]

This isn't specific to the topic, but i'm asking the question to LRD regards the max energy limits and i'd like people's experience and feedback.

Background:
338 Lapua/Norma Mag, 300nm, 300wm are the current magnums in service with most western militaries. They are getting a lot of support from manufacturers making them more easily accessible to shooters, and thus, shooters want to shoot them.
The places these rifles can be fired are limited, but they are becoming extremely popular with long range hunters for deer. This is particularly the case for 300PRC and 300NM.

A few guys have approached me to chat about the potential of a long range magnum event/discipline (Details TBC for how that would look or be integrated into the club)

I have sent this as an RFI to LRD to ask as to whether it CAN be done, before I go trying to rally support or change the world.

I don’t have a dog in this fight as I can’t afford these sorts of rifles, but I didn’t want to say “No”, without trying or without providing a proper, investigated response. I hate turning shooters away and with the increased availability of these rifles, I think it’s worth asking LRD’s support to investigate their inclusion in the sport.

Also, our LRD guys are absolute legends and never say “No”, it’s always “We’ll find out for you”. So with that kind of support, why not ask?

Identified Risks:
Most VRA ranges have a standard template applied. This is capped at 3500ftlbs Muzzle energy and 8mm maximum calibre.

Current Spec 300NM and high BC Win Mag are all sitting around the 4000-4200 ft/lbs mark.

Energy limit would based off the Mil Spec 300gr Lapua Magnum cartridge of 5000 ftlbs. Mainly because this is easily accessible and standard information and isn't subject to change.

Mitigations:
If we limited firing to 1000y and 100m we might be able to mitigate the risks associated with these heavy calibre firearms.
300gr HPBT from a Lap Mag (highest rated energy permissible) fired from 1000y is doing 1850ftlbs of energy when it impacts the target.
This is the same energy that a 308 would achieve fired from 300y (roughly - subject to barrel length, projectile weight etc etc).
So we can mitigate the energy by maximising and limiting the ranges they are permitted to be shot.

Secondarily, we need to permit members to zero. 100m puts the back stop well and truly high enough that a critical safety incident is very unlikely. So our mitigation here is the inverse. We limit the range and maximise the angle of the backstop relative to the shooter to avoid a shot going outside the trace with all it’s retained energy.

The concern arises of maintained energy post ricochet should one occur with the added mass of the heavier bullets potentially carrying them further compared to non-magnum carts that we are templated for.

It's potentially a 1%er and is very very unlikely, but it IS a 1%er. We don't want to come home from the range 99% of the time - so safety is absolutely paramount. If we can't mitigate, it's off the table.

This is where I’m currently sitting with the above sent to LRD.
I'll be having a meeting with LRD next week to discuss this and a few other things.

As good of a bunch of blokes as they are, I still want to move into the discussion armed with as much information as possible so we can work through the details effectively and get a proper, informed answer as to why these sorts of rifles can’t be included (if they can’t be). We might be pleasantly surprised, and any support we can offer to even just a small handful of shooters is still worth doing IMO.

Has anyone looked into this at all previously?

Doesn't anyone have any insight or experience?

Thanks in advance

Carso