PRS Talk Velocity Sweet Spot For PRS?

[Cardboard Assassin]

I had an interesting discussion on velocities with a PRS competitor recently. As a new PRS shooter I like to soak up all the info I can get.

When discussing 6mm caliber options it was mentioned that some shooters (even top shooters) load their rounds down (ie lower the velocity) so they can see the trace.

I forgot to ask if this meant they could not see it at all and slowing it down allowed them to or if they could see it and slowing it down let them see it easier / better.

I have never shot any of the faster 6mm calibers to see for myself (my experience is limited to 6.5CM that likes to run slower than most in the 2600s and i can see that no problem) so I'm curious what others are finding.

My understanding is that the high speeds is what makes the 6CM one of the best calibers for PRS as it can punch through the wind better so slowing it up for trace purposes kinda takes away that advantage and you may as well use one of the other slower calibers.

I have read a few times that even the 100-150FPS between calibers makes a heck of a difference in windy conditions so this information seems upside down to me.

Thoughts?

 

[Iusmc2002]

The lower the velocity, the lower the recoil. Less recoil means less rifle/scope movement after the shot. It keeps your eye in the scope, scope on the target and allows you to see the trace from the bullet

 

[Kadams1563]

6mm sweet spot? Anywhere from 2750-2850 (6BR) 2950-3050 (6GT) 2980-3100 (6creed) those are estimates lol but you get the idea.

mall of them work. For me I am in the GT class but the BR variants also work extremely well. 6creed is the hot rod and will be easier for wind calls though.

 

[samb300]

@Cardboard Assassin Higher velocity doesn’t do as much for wind as you might think. Try it for yourself in your ballistic calculator; take your bullet of choice (say 105 Hybrid) at 2800fps and at 3100fps to represent a 6BR vs 6Creed. What you’ll see in a 10mph crosswind might surprise you, you’re only a couple tenths better with a creed at 1000yds. At normal distances like 4-600yds they are essentially the same. But if you’re using a Kestel to measure wind and output a firing solution, it doesn’t really matter what your velocity is.

What it does gain you is a bit more forgiveness in wind calls (might catch an edge on a long range target), especially if you shoot in OK or somewhere where 15+ mph winds are typical. Where I shoot in the Midwest 5-7 mph is typical so there isn’t much benefit to hot rodding.

And unless you shoot field matches with UKD stages, higher velocity being “flatter” doesn’t matter either. Again, it’s just a number your Kestrel will spit out for you.

This year was my first year shooting a 6mm after shooting a 6.5x47L for 4 years. Shooting a 110 A-Tip at 2850fps out of a 6GT has essentially the same ballistics as a 140 Hybrid at 2750fps, but with 30% less recoil energy. Since most long range targets have flashers now, there’s really no downside to a slow 6mm, and little upside for me to try to push it 100fps harder.

 

[samb300]

Also, JBM has a recoil calculator. Input your bullet weight, velocity, powder charge, and rifle weight, and it spits out recoil info. Useful for comparing 6.5 to 6, or even a 6BR to a 6Creed.

https://www.jbmballistics.com/cgi-bin/jbmrecoil-5.1.cgi

 

[C.R. Adams]

On the latest Precision Rifle Media podcast they interview some of the competitors from the AG cup. at least one of the guys spends some time talking about the slower vs faster. They all talk about bullet trace. It's worth listening to.

 

[Cardboard Assassin]

@Cardboard Assassin Higher velocity doesn’t do as much for wind as you might think. Try it for yourself in your ballistic calculator; take your bullet of choice (say 105 Hybrid) at 2800fps and at 3100fps to represent a 6BR vs 6Creed. What you’ll see in a 10mph crosswind might surprise you, you’re only a couple tenths better with a creed at 1000yds. At normal distances like 4-600yds they are essentially the same. But if you’re using a Kestel to measure wind and output a firing solution, it doesn’t really matter what your velocity is.

What it does gain you is a bit more forgiveness in wind calls (might catch an edge on a long range target), especially if you shoot in OK or somewhere where 15+ mph winds are typical. Where I shoot in the Midwest 5-7 mph is typical so there isn’t much benefit to hot rodding.

And unless you shoot field matches with UKD stages, higher velocity being “flatter” doesn’t matter either. Again, it’s just a number your Kestrel will spit out for you.

This year was my first year shooting a 6mm after shooting a 6.5x47L for 4 years. Shooting a 110 A-Tip at 2850fps out of a 6GT has essentially the same ballistics as a 140 Hybrid at 2750fps, but with 30% less recoil energy. Since most long range targets have flashers now, there’s really no downside to a slow 6mm, and little upside for me to try to push it 100fps harder.

Awesome info, thank you.

Can I ask why you went with the GT? I dont know a lot about the cartridge but I know its somewhere in the middle of the spectrum, ie BR being the low end / slowest and 6 CM being the high end / fastest.

Isn't 2850 on the slow side for 6GT?

 

[Cardboard Assassin]

Also, JBM has a recoil calculator. Input your bullet weight, velocity, powder charge, and rifle weight, and it spits out recoil info. Useful for comparing 6.5 to 6, or even a 6BR to a 6Creed.

https://www.jbmballistics.com/cgi-bin/jbmrecoil-5.1.cgi

Thanks again, I have ran some numbers and there is a difference but its not massive.

I have put down a deposit on a blank barrel but I haven't committed to a caliber yet, I may play around with that some more just for fun......

 

[Cardboard Assassin]

On the latest Precision Rifle Media podcast they interview some of the competitors from the AG cup. at least one of the guys spends some time talking about the slower vs faster. They all talk about bullet trace. It's worth listening to.

Im only about 15 minutes in but it seems good.

The first guy went from a 6CM to a 6 Dasher as he felt with the 6CM he was constantly load developing / chasing throat erosion, he went so far as to say that even a match would be enough to have to measure again to find the sweet spot.

 

[Mormegil87]

Awesome info, thank you.

Can I ask why you went with the GT? I dont know a lot about the cartridge but I know its somewhere in the middle of the spectrum, ie BR being the low end / slowest and 6 CM being the high end / fastest.

Isn't 2850 on the slow side for 6GT?

I ran GT at 2820. I went away from it because why use 34 grains of Varget to get 2820 when I can use 31 grains out of the BRA.

Speed definitely isn't all its cracked up to be.

 

[Newbie2020]

Is the BRA case that superior in burn efficiency vs the GT case that I can get the same muzzle velocity with 9% less powder?

 

[Mormegil87]

@Newbie2020 I have no idea. I know guys that were running GT with 34 - 34.5gr of Varget powder at 2900+. I also know guys running BRAs at 2900+. I personally run everything slow. My BRA load is 30.6 of Varget at 2820. I'm not sure what I'm going to need for a charge weight with 4895 to get to 2820ish.

 

[Newbie2020]

There are some good shooters on here who absolutely trust the BR-based case for consistency and accuracy for whatever reason.

 

[Mormegil87]

The BRA is my favorite case so far. Easy to load for, can shoot matches while fire forming. Haven't had to tune anything so far.

As @samb300 can attest I have shot a lot of different cases over the years.

 

[Darkside-Six]

This was my first year shooting a 6mm from shooting 6.5 CM for the last 6-7 years. I was leaning towards the 6mm creed moor but didn’t like the barrel life compared to that of the GT so went with the GT. I ran mine at 2870 for most of the year and couldn’t be Happier. Very low recoil, flat shooting as hell. Never was one to chase speed. Saves a little on barrel life as well going slower.

 

[samb300]

Awesome info, thank you.

Can I ask why you went with the GT? I dont know a lot about the cartridge but I know its somewhere in the middle of the spectrum, ie BR being the low end / slowest and 6 CM being the high end / fastest.

Isn't 2850 on the slow side for 6GT?

The biggest reason for shooting 6GT is I shoot a factory AI rifle so 6BR-based cases can be hit or miss for 100% reliable feeding. And like you said it’s in between BR and Creedmoor, so I’m not using 42gr of powder and burning out a barrel, or trying to load a Creedmoor down and dealing with high SDs.

I shoot a 24” barrel suppressed, so my velocities are always slow compared to most. I also don’t chase velocity. Most guys with 109/110s and 26” barrel are around 2900-2950 with a 6GT.

 

[beetroot]

@Cardboard Assassin Higher velocity doesn’t do as much for wind as you might think. Try it for yourself in your ballistic calculator; take your bullet of choice (say 105 Hybrid) at 2800fps and at 3100fps to represent a 6BR vs 6Creed. What you’ll see in a 10mph crosswind might surprise you, you’re only a couple tenths better with a creed at 1000yds. At normal distances like 4-600yds they are essentially the same. But if you’re using a Kestel to measure wind and output a firing solution, it doesn’t really matter what your velocity is.

Agreed.

OP.
The current trend of 6mm cartridges is all about reducing recoil whilst trying to keep good ballistics and acceptable barrel life.
I personally would rather sacrifice a little speed and go for a 6BR over 6mm CM; the longer barrel life, less powder and the ease of finding a good load are worth trading a few hundred FPS (if that).

I shot a match recently with two guys shooting 6mm CMs, a mate shooting a 223 and myself with my 6.5mm CM.
It was a very windy day and caused everyone a lot of grief, my mate with the 223 had a very bad day.
The 2 guys with the 6mm CMs had noticeably more trouble in the wind than I did shooting 147 ELDs, I compared wind holds with them all day and my holds were noticeably less and I had less trouble in the switching winds.

For the type of shooting I do I'm better off sticking to my 6.5mm CM and dealing with a bit more recoil.

TLDR;
Any 6mm cartridge will be close enough in velocity that a few FPS here and there wont be the deal breaker for the majority of shooters.
The 6mm craze is all about reducing recoil but you do pay a penalty in wind drift vs a higher BC 6.5/7mm/30cal (within reason).

 

[Cardboard Assassin]

On the latest Precision Rifle Media podcast they interview some of the competitors from the AG cup. at least one of the guys spends some time talking about the slower vs faster. They all talk about bullet trace. It's worth listening to.

Thanks for the link.

I finished listening to the interviews and there was a ton of good information there, I now have no concerns about going with the slower speeds of BR / BRA as many of the accomplished shooters are moving in a similar direction for trace purposes.

 

[Newbie2020]

Does BR deed well from a AICS mag? Or will I need an adapter?

 

[Cardboard Assassin]

Does BR deed well from a AICS mag? Or will I need an adapter?

I'm going with MDT mags which are purpose built for the shorter BR style cases.

From what I can tell form other users and Youtube etc they work well.

There are adaptor kits out there but I cant speak as to how well they work.

 

[Newbie2020]

MDT mags are getting really positive reviews

 

[Mormegil87]

I had really good lucky with a straight up AIC mag and BR in a Manners TCS. My Foundation seems to like the MDT mags with built in spacers.

 

[Cardboard Assassin]

MDT mags are getting really positive reviews

I hope so, I've got 2 on the way.

They seem well made (that has been my experience with all MDT gear to date), sounds like they feed well and have 12 round capacity.

 

[Newbie2020]

nice

 

[Newbie2020]

Kicking myself for not ponying up during the MDT black friday sale on mags. Other priorities took my money...

 

[Dthomas3523]

2775-2950

My experience has been that 3k is where recoil increase and barrel life decrease becomes more evident. As others have said, the wind gains are very small past that. And not exploitable by most.

For example, in a podcast Dave Preston said he went back to 6cm for a while because he would pick up a point or three on long range stages where he’d clip the edge instead of miss.

Point being, you need to be at that level where getting an edge hit at distance on one stage in a match is the difference between winning and losing. So, until at that level, I wouldn’t concern myself with it.

 

[Cardboard Assassin]

2775-2950

My experience has been that 3k is where recoil increase and barrel life decrease becomes more evident. As others have said, the wind gains are very small past that. And not exploitable by most.

For example, in a podcast Dave Preston said he went back to 6cm for a while because he would pick up a point or three on long range stages where he’d clip the edge instead of miss.

Point being, you need to be at that level where getting an edge hit at distance on one stage in a match is the difference between winning and losing. So, until at that level, I wouldn’t concern myself with it.

Makes sense.

I'm certainly not at the level where it would make a difference so the ease of tuning, reduced recoil and potentially double the barrel life of the 6BR calibers are probably a better fit for me.

 

[Newbie2020]

2775-2950

My experience has been that 3k is where recoil increase and barrel life decrease becomes more evident. As others have said, the wind gains are very small past that. And not exploitable by most.

For example, in a podcast Dave Preston said he went back to 6cm for a while because he would pick up a point or three on long range stages where he’d clip the edge instead of miss.

Point being, you need to be at that level where getting an edge hit at distance on one stage in a match is the difference between winning and losing. So, until at that level, I wouldn’t concern myself with it.

really learning good point for me as a noob. I don’t need 1-3 points I need 30!

6cm
6GT
6Dasher
6br

As I rebarrel my 6.5cm, I’m leaning towards the 6br to cut recoil until I’m better at recoil management. Is that smart or dumb?

 

[LV Precision]

MDT mags are getting really positive reviews

MDT BR mags feed great for my Dasher. Just need to tune the feed lips to get the right positioning for the round, and then it feeds fantastic for an out of the box solution. Great that it comes standard for 12 rounds without buying an additional extension.

 

[Cardboard Assassin]

really learning good point for me as a noob. I don’t need 1-3 points I need 30!

6cm
6GT
6Dasher
6br

As I rebarrel my 6.5cm, I’m leaning towards the 6br to cut recoil until I’m better at recoil management. Is that smart or dumb?

Depends how you look at it. Moving from a 6.5CM to any of the smaller calibers will seem easier due to the reduced recoil.

In the past I raced motorcycles and where possible I would practice on one size bigger than I would race (ie, race on a 250, practice on a 500 / race on a 125, practice on a 250) and I found it worked well. When I got on the smaller bike it felt like a toy and everything seemed easier than the more powerful practice bike.

Using the same logic I'm keeping my 6.5CM as a practice rifle. Obviously the larger caliber will have more recoil to deal with so any improvements will be more noticeable. Of course anything I learn can be carried across to the smaller calibers.

 

[Newbie2020]

I do like my 6cm. But I’m pondering going even lower both for recoil and barrel life

 

[Cardboard Assassin]

I do like my 6cm. But I’m pondering going even lower both for recoil and barrel life

There is a definite trend towards exactly that right now

Edit - the PRS podcasts referred to earlier in this thread have a ton of good info for anyone considering moving away from the faster 6mm cartridges towards the slower versions. The info helps alleviate some of the concerns.

 

[Dthomas3523]

really learning good point for me as a noob. I don’t need 1-3 points I need 30!

6cm
6GT
6Dasher
6br

As I rebarrel my 6.5cm, I’m leaning towards the 6br to cut recoil until I’m better at recoil management. Is that smart or dumb?

Here’s another big tip. If you take all those you listed, take for example a 109 Berger and push it 2950 out of all four of them......it does the exact same thing.

So, IMO, there’s only a choice to be made on barrel life and recoil (super minor differences).

The larger case (6cm and 6x47) have a different recoil impulse “feel” than the smaller BR case. However the BR case will save you a bunch of powder in the long haul. But recoil feels different.

 

[Newbie2020]

^^^^thanks Dave. Good insight.

So given our current powder predicament, br makes even more sense!

 

[jinxx4ever]

MDT mags are working great in my dasher

 

[Dthomas3523]

^^^^thanks Dave. Good insight.

So given our current powder predicament, br makes even more sense!

Generally speaking here’s what you get in an 8lb jug of varget:

30gr = 1850 rnds
32gr = 1750 rnds
34gr = 1650 rnds
35gr = 1600 rnds

Further reference I use:

30gr in BR case = 2800 fps
32gr in dasher = 2900 fps
34gr in 6gt = 2950 fps
35gr in 6x47 = 2950 fps

So, you can get 100-250 more rounds in a 6br or dasher/6bra/6brx running 2800 vs the 6gt/6x47 running 2950.

 

[Gettingbetter]

On the latest Precision Rifle Media podcast they interview some of the competitors from the AG cup. at least one of the guys spends some time talking about the slower vs faster. They all talk about bullet trace. It's worth listening to.

Cany you post or send the link for this podcast?

 

[NiteQwill]

Cany you post or send the link for this podcast?

Precision Rifle Media

Welcome to Precision Rifle Media sponsored by Bison Tactical. Bison Tactical makes competition proven gear like the Tactical Udder, Durable Wind Flag and Tiny Rear bag. They also sell the gear you need for long range precision, like firearms from JP Rifles, Desert Tech and Zermat Arms to suppresso

www.precisionriflemedia.com

 

[iceng]

Last season I ran nosler 105gr 6mm in a 243 Ackley. I ran them at 2805fps. In Australia, we mostly shoot on square ranges, out to 500m

Zero at 100, 200m is 0.5mil, 300m is 1mil, 400m is 2mil, 500m is 3mil.
Recoil was non existent, barrel life was good (2992 round before I pulled it) and it made holding over / under a breeze. That's why I chased a low velocity.

Currently I'm on 108gr eld-m. I have a good node at 3070fps, but will be backing it down to try and reproduce the "easy drop per distance"

 

[Cardboard Assassin]

Last season I ran nosler 105gr 6mm in a 243 Ackley. I ran them at 2805fps. In Australia, we mostly shoot on square ranges, out to 500m

Zero at 100, 200m is 0.5mil, 300m is 1mil, 400m is 2mil, 500m is 3mil.
Recoil was non existent, barrel life was good (2992 round before I pulled it) and it made holding over / under a breeze. That's why I chased a low velocity.

Currently I'm on 108gr eld-m. I have a good node at 3070fps, but will be backing it down to try and reproduce the "easy drop per distance"

This ^^^^ is great info.

Having a setup like this would sure make it simple to make hits on the fly while on the clock.

 

[iceng]

PRS

PRS skill stage 4 - rules, stage layout and gong sizes in link (and sale if in AU, I'm not affiliated with them, but do know them as they sponsor PRS AU)
Often on "square" ranges, so distances get jigged a bit. Holding common numbers makes it easy.

 

[bschneiderheinze]

I think some people are lacking fundamentals. I’ve seen my 120lb son clear 5-6 position barricades in time running a BRX at 3060. Honestly I can’t tell the difference in his brx and my 223 both with Area 419 breaks. If the lower speed gets you in accuracy node it’s great but I like bucking the with 3060-3080 compared to 2850

 

[iceng]

I guess it's all relative to what's important to you. Wind, drop, recoil, weight, maneuvering, etc.

Good, cheap, fast.. pick 1.

 

[Dthomas3523]

I think some people are lacking fundamentals. I’ve seen my 120lb son clear 5-6 position barricades in time running a BRX at 3060. Honestly I can’t tell the difference in his brx and my 223 both with Area 419 breaks. If the lower speed gets you in accuracy node it’s great but I like bucking the with 3060-3080 compared to 2850

I think you’re just not shooting enough to tell the difference.

There’s a very noticeable difference in a brx and a .223. Should you be able to shoot them the same? Of course. But they don’t recoil or feel the same.

We are talking small differences that matter to top shooters. You’re also not bucking wind at the common distances in 3050 vs 2850. 800+ is the only time this comes into play and that’s the smallest % of shots at a match.

 

[Tokay444]

really learning good point for me as a noob. I don’t need 1-3 points I need 30!

6cm
6GT
6Dasher
6br

As I rebarrel my 6.5cm, I’m leaning towards the 6br to cut recoil until I’m better at recoil management. Is that smart or dumb?

I don’t think you get better at recoil management by shooting a rifle with less to no recoil.
I’m a huge 6BR fan for its inherent accuracy and would never steer you away from it, but I think a bit of your logic is flawed there.

 

[Dthomas3523]

If it were me, I’d run .308 a lot in practice for better recoil management. Then the 6mm at matches.

Kinda like warm up swings with weight on a baseball bat before stepping into the box.

 

[bschneiderheinze]

I shot 8000 rounds last year I think I can judge recoil. My 223 shoots a pretty stiff load.

I think you’re just not shooting enough to tell the difference.

There’s a very noticeable difference in a brx and a .223. Should you be able to shoot them the same? Of course. But they don’t recoil or feel the same.

We are talking small differences that matter to top shooters. You’re also not bucking wind at the common distances in 3050 vs 2850. 800+ is the only time this comes into play and that’s the smallest % of shots at a match.

 

[bschneiderheinze]

They have near the same ballistics at least with 80 eld you can a 223 come close to match 6mm ballistic.

If it were me, I’d run .308 a lot in practice for better recoil management. Then the 6mm at matches.

Kinda like warm up swings with weight on a baseball bat before stepping into the box.

 

[NiteQwill]

They have no near the same ballistics at least with 80 eld you can a 223 to come close to match 6mm ballistic.

what?

 

[iceng]

I just rebarreled a customers 223 into a 223ackley, with the the throat pushed back some. 88gr Berger's. Has almost identical drop / drift to 500m as his 6cm. For half the powder.