20” 7mm Rem Mag, suppressed????

[landoncooley]

Hello,

I have a Tikka T3x Lite in a 7mm Rem Mag. I have been wanting to cut it down to a 20” barrel because I am going to be running it suppressed.

I know I will loose velocity, but I am currently getting 3000+ FPS out of the factory 24” barrel and I think the lessened velocity with be manageable. I am concerned about overall noise and muzzle flash when not shooting suppressed.

Has anyone ever done anything like this with a magnum caliber?


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[Oldffemt]

I cut my 300wsm down to 21”. It’s loud when shot unsuppressed. I’m still getting north of 3100fps with a 165 ab. I haven’t had time to play with any other bullets yet.

 

[landoncooley]

I cut my 300wsm down to 21”. It’s loud when shot unsuppressed. I’m still getting north of 3100fps with a 165 ab. I haven’t had time to play with any other bullets yet.

Nice! Do you feel the noise is any different when suppressed?


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[Bighorner]

I cut my 7 RM to 22" and did not notice a change in the noise or the muzzle flash.

 

[Oldffemt]

My can uses a brake/qd taper mount. It directs the blast to the side/rear so yeah, it’s louder. But your post says you plan to run suppressed so what’s the issue? If all goes well, I shoot about 6 rounds a year Unsuppressed through mine cause I don’t carry the suppressor in the mountains. 4-5 to confirm zero and 1-2 to fill tags.

 

[OG-danimal]

Just now reading this post and wondering how it turned out? I want to do the same thing with my tikka t3x lite I bought in 7mag. Any suggestions or things you’d do different?

 

[280twoeighty]

Same here. I would like to cut and thread mine to 18 or 19" . It is a tikka 7RM also. It is for a suppressor also. Thoughts. Thanks guys.

 

[Kerbs]

I cut a 30-06 Tikka down to 20" and had it threaded. I run a TBAC 5 or 7 on it with the TBAC brake. The one thing I would check is that you have enough barrel diameter at 20"s to create an adequate shoulder for the suppressor. My smith had to create a larger shoulder to mount the brake to. Just something to consider. Most suppressor manufactures will have drawings of the threading and shoulder needed.

 

[steffen707]

Just now reading this post and wondering how it turned out? I want to do the same thing with my tikka t3x lite I bought in 7mag. Any suggestions or things you’d do different?

Same here. I would like to cut and thread mine to 18 or 19" . It is a tikka 7RM also. It is for a suppressor also. Thoughts. Thanks guys.

Hey, guess i'm joining the club. I too bought a tikka t3x lite in 7mmRM. I'm planning to get a 18-20" proof barrel with carbon fiber stock and just got my thunderbeast 7" suppressor. I wanted 18-20 so that the overall length only increases 1-3 inches. I figure if I get an accurate load, i can just adjust the scope more to kill something out to 400-600.

Did @landoncooley, @djprice91 or @280twoeighty actually shoot a 18-20" 7mmRM yet? I haven't.

 

[OG-danimal]

Not yet, just waiting on my can to come in. Still undecided on how much I want to cut off the stock 24” barrel. I was thinking cut it to 20”

 

[steffen707]

Not yet, just waiting on my can to come in. Still undecided on how much I want to cut off the stock 24” barrel. I was thinking cut it to 20”

I keep flopping between 18" and 20".

 

[landoncooley]

Yes so I went to 20” suppressed and it shoots great! I’m shooting factory ammo (hornady precision hunter 162 gr eldx). Still getting just over 3000 fps and it shoots sub moa. Overall awesome build and I wouldn’t change anything.

I would be hesitant to go under 20” based off my research. I was hesitant to even go to 20” with a mag caliber. I have not had any issues and my velocities are still great but there is an argument that with some loads in a mag caliber less than 20” may not provide enough barrel length for the powder to burn off.

I packed mine all over the back country this fall and it went great as far as the overall length is concerned.

LOVE THIS GUN!


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[280twoeighty]

Thanks Landon for the info. Sounds like a great set up.

 

[Doc Holliday]

People say "what's the point in having a magnum if you have a short barrel", but the reality is its cheaper to cut and thread a barrel than it is to buy a new rifle.....not to mention you may have a bunch of memories with that magnum rifle, and want to make more, in a different configuration.

 

[zion zig zag]

Yes so I went to 20” suppressed and it shoots great! I’m shooting factory ammo (hornady precision hunter 162 gr eldx). Still getting just over 3000 fps and it shoots sub moa. Overall awesome build and I wouldn’t change anything.

I would be hesitant to go under 20” based off my research. I was hesitant to even go to 20” with a mag caliber. I have not had any issues and my velocities are still great but there is an argument that with some loads in a mag caliber less than 20” may not provide enough barrel length for the powder to burn off.

I packed mine all over the back country this fall and it went great as far as the overall length is concerned.

LOVE THIS GUN!


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I have the same gun, can you post photos of it cut down?

There are all kinds of articles about velocity lost per inch with 308 and 6.5 CM but I don't see anything for 7mm RM. Anyone have any data?

 

[WeiserBucks]

Here's a simple fact that applies to all of these "Should I chop my magnum barrel" threads.


A short barreled magnum will have faster velocity than a short barreled standard cartridge with a given bullet weight. Are they efficient? Of course not. Are they a flame thrower without a suppressor? Hell ya. But they're the only way to drive a heavier bullet at the highest velocity possible with a short barrel.

 

[steffen707]

I have the same gun, can you post photos of it cut down?

There are all kinds of articles about velocity lost per inch with 308 and 6.5 CM but I don't see anything for 7mm RM. Anyone have any data?

I'm thinking of trying this myself. Take my 24" tikka 7RM and get magnetospeed data on my best load (just bought a v3), chop 2" off and retest velocity, chop 2" more off and test, then chop 1.5" more to 18.5", if its decent, take it to a smith and get barrel cut threaded at 18" and roll with it with my Ultra 7 can. I already have a cold steel saw.

OR, I might chop to 18.5" and if its decent, get a 18"proof barrel, new stock and do a build using the tikka action and trigger, or if at 18.5" it can't achieve my speed needs of 2850-2900, then buy a 20" proof, new stock and build with tikka action/trigger.

I always have trouble re-finding this article, but its a good one.

7mm Remington Magnum (7 Rem Mag) Barrel Length Versus Velocity

7mm Remington Magnum (7 Rem Mag) Barrel Length Versus Velocity Since its introduction in 1962, the 7mm Remington Magnum (7 Rem Mag) has developed a strong following, becoming the most popular metri…

rifleshooter.com

I know at 20" he wasn't getting 2900fps, but he also using factory ammo.


If I can get a stable load and decent groups and still 2850-2900fps, it'll be adequate out to 500-600 yards as far as ft/lbs of energy and velocity over 2000fps to get good bullet expansion.

No I have never shot an animal or target out to 500-600, but I want to someday.

I think most of these threads (and i've started a few myself) are people wanting to have their cake and eat it too VERSUS people who either wish they had the guts/$$$ to try it themselves, or people who have just heard/read that others say short magnums are bad/loud/dumb, ect.

I think very few people have actually done it.

Who knows I might spend an extra $1,000 or cut down a perfectly fine rifle and get some "i told you so's" but at least i'll know for sure. I'll be sure to post my results, good/bad/indifferent. I just got my ultra7 out of jail, so after hunting, i'm going to start the build/cut/whatever.

 

[ID_Matt]

Here's a simple fact that applies to all of these "Should I chop my magnum barrel" threads.


A short barreled magnum will have faster velocity than a short barreled standard cartridge with a given bullet weight. Are they efficient? Of course not. Are they a flame thrower without a suppressor? Hell ya. But they're the only way to drive a heavier bullet at the highest velocity possible with a short barrel.

100% agree with this. More velocity = more velocity whether it is efficient or not. I see that argument come up all the time when guys get super short barrel 6.5 PRC's. Usually see a comment like - "Why would you do that, those are creedmoor speeds".... Yes, a 20" PRC will produce 26" creedmoor speeds, NOT 20" creedmoor speeds. Apples to apples.

 

[steffen707]

Yes so I went to 20” suppressed and it shoots great! I’m shooting factory ammo (hornady precision hunter 162 gr eldx). Still getting just over 3000 fps and it shoots sub moa

Dang, that must be a hot factory load! Either that, or i'm a wuss and need to up my powder charge and learn more about "pressure signs".

 

[WeiserBucks]

I'm thinking of trying this myself. Take my 24" tikka 7RM and get magnetospeed data on my best load (just bought a v3), chop 2" off and retest velocity, chop 2" more off and test, then chop 1.5" more to 18.5", if its decent, take it to a smith and get barrel cut threaded at 18" and roll with it with my Ultra 7 can. I already have a cold steel saw.

OR, I might chop to 18.5" and if its decent, get a 18"proof barrel, new stock and do a build using the tikka action and trigger, or if at 18.5" it can't achieve my speed needs of 2850-2900, then buy a 20" proof, new stock and build with tikka action/trigger.

I always have trouble re-finding this article, but its a good one.

7mm Remington Magnum (7 Rem Mag) Barrel Length Versus Velocity

7mm Remington Magnum (7 Rem Mag) Barrel Length Versus Velocity Since its introduction in 1962, the 7mm Remington Magnum (7 Rem Mag) has developed a strong following, becoming the most popular metri…

rifleshooter.com

I know at 20" he wasn't getting 2900fps, but he also using factory ammo.
View attachment 344830

Hopefully folks will take this chart with a grain of salt, that ammo used is pathetic at best. My 24" 7 RM makes 2925 FPS with a 180 Berger and it'll go faster safely but accuracy falls off.