Integrally Suppressed "Magnum DeLisle" Rifle Build

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FizzyP

New member
A while back I first heard about the integrally suppressed, bolt action .45 ACP "DeLisle Carbine" and it got my imagination working. Wouldn't a "big boy" version be a truly great rifle? (Google the DeLisle Carbine if you haven't heard of it. It's a very cool idea.)

If you wanted a magnum DeLisle how would you build it?

It would be fun and pleasant to shoot and at the same time a legitimately useful hunting rifle. Various people make a nice modern version based on the Ruger 77/44, but that gun is famously mediocre accuracy-wise (the rear locking lug design is questionable). Also, it's still a pistol caliber carbine and I'd like something with a little more thump.

These are my criterion:

  1. Fun to shoot for everyone (including kids and small women)
  2. Will safely take any game in North America.
  3. Is a repeater with a magazine capacity of at least 3 rds
  4. Accurate (1 MOA would be nice)
  5. Reasonably handy. I don't require a compact brush gun but I don't want a 15 lb bench rest rifle either. Keeping it to 8.5 lbs and at most a 24" tube would be nice.
  6. Integrally suppressed.
  7. Bolt action (although I'm flexible on this)
Points 1 and 2 may appear to be in contradiction but I reload, so assembling my own soft-shooting rounds is easy. The one compromise I'm willing to make (have to make) is that it doesn't need to be long range rifle. Flat enough out to 200 yds is plenty.

Also, I'd like to be able to put together the following loads:

  1. A subsonic hearing-safe load that's relatively low recoil and pleasant to shoot for everyone. With the right bullet choice the subsonic load should be effective for hunting CXP2 class game at close range.
  2. A higher velocity flatter shooting bullet with an OK BC that's good for CXP2 game out to at least MPBR.
  3. A heavier bullet option with good SD for CXP3 game.
  4. Nice to have: a non-expanding Grizzly stopper.
Any ideas? Am I asking for too much from one rifle and need to make some compromises? How would you build it?
 
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Best ideas so far

Here is my thinking on the build so far. I'm not married to any of these choices, so please present alternative ideas if you have them. As far as calibers go, something big bore seems like a good idea for the following reasons:

* For a subsonic load you're stuck with ~1000 FPS, so the only way to increase effectiveness on game is by using heavy bullets with large frontal area.
* Big bore cartridges generally aren't very over-bore, so the ballistics aren't hurt as much by the ported barrel in an integral suppressed rifle.

Of the big bores, 45 cal has the most plentiful bullet selection. The chamberings I've been considering are 45-70, 450 Marlin, and 458 Win Mag. Again, please suggest other chamberings with other bore diameters if you have good ideas.

In 45 cal the following loads would satisfy my load requirements listed above.
1. A 400+ gr bullet at 1000 fps (the recoil is negligible, satisfying the kids and small women criterion)
2. A 300 gr bullet at 2500 fps (The 300 gr Barnes Original semi-spitzer soft point looks superb and has a great BC considering how short and fat it is.)
3. A 400+ gr soft point north of 2000 FPS (The 400 gr Barnes Original also looks excellent).
4. A 400+ gr hard cast wide-meplat style bullet at any velocity.

The 45-70 and 450 Marlin both seem to fit the bill. But, I'm concerned that the top end velocity would suffer greatly in an integrally suppressed gun and a goal like 300 gr at 2500 would no longer be possible.

The .458 Win Mag would solve this problem with extra powder, but I'm concerned accuracy would suffer with lighter 300 gr bullets. There are a lot of people online claiming mediocre results with lighter bullets in .458 Win Mag. Possibly this is due to the faster twist rate? The same people consistently report accuracy improves the closer you get to the traditional full house loads with heavy bullets. Recoil sensitivity isn't really a problem for me. But, at the same time, the idea of having to bring scorching dangerous game class 400+ gr loads to hunt deer is not too appealing. Another concern is that the case capacity is prohibitively large for a subsonic loading.

Ultimately this will probably be a custom rifle built from scratch. A modern Mauser action is an obvious platform candidate. Any recommendations?
 
I'd look at a .458 American. It is in the same ballpark as strong action .45-70 or .450 Marlin but has the standard H&H belt instead of the .45-70's rim or the Marlin's odd wide belt. Made by shortening almost any belted brass you might have around to 2" case length. But that does mean you have to be careful to keep it out of the parent bottleneck chamber. Squeezing a .458 down to 7mm would be hazardous to your health.
On second thought, consider the Marlin unless the American was your only belted magnum.

There is no way to make a flat shooting high speed rifle out of a .45, take what it gives you.

I have read that the .458 Win Mag's shortcoming with light bullets is its long tapered throat meant to ease steel jacketed buffalo bumpers into the rifling. A gunzine writer once had a reamer ground to just take a 350 grain bullet and it was as fast a .45 as you are likely to see.
 
The 45-70 and 450 Marlin both seem to fit the bill. But, I'm concerned that the top end velocity would suffer greatly in an integrally suppressed gun and a goal like 300 gr at 2500 would no longer be possible.
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Not sure (besides the legal complications) what an integrally suppressed barrel will do for the velocity of loads. I assume you're interested in integrally suppressed to avoid the extra size, weight and length of an attached suppressor?

What I am sure of is that you won't get 2500fps with a 300gr bullet from any sane .45-70 or .450Marlin load and barrel length. With MAX loads in a Ruger single shot or suitable bolt action you can get 2200fps, possibly 2300fps.

Top end loads in .458 Win Mag get that 300 to 2500fps. But those are max too. Likewise the 400gr at 2000+, just a bit beyond what the ,45-70/.450 Marlin can do, but possible with the .458 Win.

BC of .45 cal rifle bullets? is that going to matter?? Is it a practical matter if bullet A drops 80" and better BC bullet B only drops 75"??

Flat enough out to 200 yds is plenty.
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Not sure what you consider "flat enough" but no .45 cal rifle is going to be stretched string/laser beam flat, not even close.

Just FYI, in the US, under current law, that integrally suppressed barrel will need ATF approval, BEFORE you start to build it. Otherwise, it's breaking the law. Good Luck!



Accuracy of short (300gr) bullets?? Maybe, maybe not so much. How much difference is being reported?? No matter what it is, every rifle barrel and load combination are different and can give different results. The only way to know, for certain is to test in YOUR barrel.
 
so the ballistics aren't hurt as much by the ported barrel in an integral suppressed rifle.
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You are going to have a hard time getting a 2500 fps velocity from a ported barrel. If a hot rod 45 caliber rifle is your goal, you'd better look into a muzzle mounted suppressor instead.
 
FizzyP said:
In 45 cal the following loads would satisfy my load requirements listed above.
1. A 400+ gr bullet at 1000 fps (the recoil is negligible, satisfying the kids and small women criterion)
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Granted I can't really factor in the recoil reduction of a suppressor very well a 400 grain bullet at 1000 fps will have between 14-15 ft-lbs of recoil energy with an 8lb rifle (same as DeLisle). That is roughly the same amount of recoil as you'd get from a 7lb .30-30 rifle. Which certainly a lot of people can shoot enjoyably, but others cant. To get the recoil down to .223 levels the rifle would have to weigh over 16lbs, which isn't enjoyable to shoot unless it is on bags, bipod, or tripods.

I seriously think your best bet to reach all your criteria would be to go to a smaller bore diameter. That way you can take advantage of higher BC bullets to accomplish your goals beyond recoil friendly. A subsonic 250 grain bullet out of a .338 Federal is right at 7lbs .223 recoil energy from an 8lbs rifle. Plus a 250 grain bullet like a Nosler Partition with a MV of 2300 fps would be a good bear stopper, plus it'll have better BC than any .45 cal 300 grain bullet so you don't need a 2500 fps MV.
 
a 400 grain bullet at 1000 fps will have between 14-15 ft-lbs of recoil energy with an 8lb rifle (same as DeLisle).
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Disagree. Wiki says the DeLisle was 7lbs 8oz, empty, but even at 8lbs there is no WAY a 400gr bullet at 1,000 fps will recoil the same as the 230gr .45ACP round.

Note that the standard factory load .45-70 round, approximating the black powder load is a 405gr bullet at approximately 1300fps. So a 400gr at 1,000fps is a bit less than that, but way more than a 230gr at 900or even 1,000 (IF the DeLisle even got that much, from its listed 8.27" barrel.

If you only meant same WEIGHT rifle as the DeLisle, and not the same recoil, it wasn't clear to me.
 
I meant that an 8lbs rifle would be the same as a DeLisle weight, as I was rounding up for simplicity. Of course I think an integrally suppressed .45 caliber rifle capable of pushing a 300 grain bullet to 2500 fps would be extremely heavy. A DeLisle only has a barrel slightly over 8" under all that suppressor, you'd need a much longer barrel than that to even get close to 2000 fps with any bullet.
 
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Why reinvent the wheel? The Ruger 77/44 is what you're looking for, and there are integrally suppressed versions for sale by custom smiths. 44 Magnum (plenty to take almost any game in NA), magazine holds 4 IIRC, recoil is tolerable for kids, and if you choose to go non-suppressed you can use it right out of the box.
 
no-go-to-slow

@Willie_Lowman Thanks for breaking the hard truth to me. The low velocity out of a ported barrel is exactly what I was worried about.

Do you think a cartridge that started with a higher velocity would do better? What about a .375 Ruger? Wikipedia lists 270 gr at 2840. Maybe almost 2500 FPS with the ported barrel? (I really have no idea) Then the question becomes can I load it subsonic?
 
@44AMP "I assume you're interested in integrally suppressed to avoid the extra size, weight and length of an attached suppressor?" <-- yes Regarding velocities achievable in 45-70/450 Marlin, the Barnes load data has several loads with 300 gr bullets at >2500 FPS from the 45-70. I know I won't be able to achieve this with a ported barrel. I wonder what the actual performance would be. The motivation for .458 Win Mag was to overcome this limitation by throwing more powder at the problem. There are .458 Win Mag loads pushing 300 gr bullets at 2700 but I suspect that's still not enough to overcome the porting. Regarding BC of .45 cal bullets I'm not trying to reduce holdover. The slightly longer MPBR and better retained energy seemed like a nice benefit. The .291 BC Barnes Original does quite a bit better than the traditional flat point bullets with BCs < 0.2 according to the calculators.
 
@taylorce1 I loaded some 405 gr bullets over 14 gr of Trail Boss in a 45-70 and it felt like a pop gun. No chrony but it could be like 800 fps for all I know. The rifle is a bit heavy (10 lbs with scope) which helps. But still it feels like nothing. My dad shot it and was immediately grinning like a child.

Regarding "go to a smaller bore diameter", you might be right. My worry is that more overbore = worse performance out of a short barrel and also harder to load subsonic. Is there a sweet spot? What caliber do you think I could pull it off with?

@Scorch The Ruger 77/44 was my motivation for all of this. The things I don't like about it are: 1) famously medicore accuracy, 2) definitely a 100 yd gun and not a 200 yd gun. If it shot 1" groups I'd be all over it. Everywhere online I see people saying the best you generally get out of commerical ammo is like 2.5" groups and with certain hand loads you might get to 1.5" groups. Sure every rifle is different but this is a big project to start out with a so-so platform. For plinking purposes I'd like more accuracy.

@ruggyh When you say "simply suppress" what do you mean? A can won't reduce velocity. A ported barrel will. 460 Mag has less case volume than 45-70 so that probably won't be enough powder.
 
Better caliber choice?

A lot of people are suggesting .458 might not be the best bore diameter. Is there a caliber that you can integrally suppress and get
  1. an accurate subsonic load
  2. an accurate CXP2 class load with 3" MPBR at least 200 yds?
 
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FizzyP said:
If you wanted a magnum DeLisle how would you build it?
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I'll answer one of your first questions and then I'll get to the one you directly asked me. To answer this one I wouldn't, because of the expense. I've dreamed of very expensive rifle builds but in the end they stayed dreams. Usually because I found a cartridge rifle combo that did the same thing and didn't cost nearly as much as my planned build.

1. To get .458 WM performance you need a .458 WM length barrel of 22+ inches. Add the suppressor baffles and you're fast approaching 30" of barrel length or more.

2. Building a faux DeLisle suppressor with an off the shelf suppressor is going to require a .50 BMG suppressor to handle the gasses of the .458 Win Mag, unless you take it off to shoot full power loads.

3. Building an integral suppressed full power .458 Win Mag, even if the suppressor is built from 100% titanium will be impossible to meet a 8.5 lbs weight limit.

FizzyP said:
@taylorce1 I loaded some 405 gr bullets over 14 gr of Trail Boss in a 45-70 and it felt like a pop gun. No chrony but it could be like 800 fps for all I know. The rifle is a bit heavy (10 lbs with scope) which helps. But still it feels like nothing. My dad shot it and was immediately grinning like a child.
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I figured you'd say something like Trail Boss and that was my first thought as well. It seems like around 20 grains of it will be the sweet spot for subsonic loads. That should get you around 11 ft-lbs of recoil energy at 8.5 lbs. Less than a .243 but more than a 7.62X39. However, in my research people were posting this wasn't enough velocity to stabilize a 400+ grain cast bullet properly to get acceptable accuracy at 1000-1100 fps.


FizzyP said:
1. an accurate subsonic load
2. an accurate CXP2 class load with 3" MPBR at least 200 yds?
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Now does this mean you can't build a DeLisle style rifle and meet your expectations. No! I don't think it can be done in a .458 Win Mag. I think .308 Win or .338 Federal (8.6 Creedmoor possibly) would be your best choices, since you can get pretty good performance out of a 16" barrel. Plus with smart choices on the build, you can probably stay close to if not within your weight and barrel length parameters.

For example if you get 2400 fps out of a 165 grain boat tail bullet in the .308 out of a 16" barrel then you have a MPBR of 239 yards with a target radius of 3". A 2400 fps 180 grain .338 Nosler Accubond gives you a 237 yard MPBR on a 3" radius target. That's plenty of power and bullet to take CXP2 game at those ranges as well.
 
.454 Casull with heavy bullets? It could also shoot .45 Colts, including the "Ruger" hot rod loads. In fact, I think those will probably be the sweet spot.
 
14 grains of Trail Boss is a full grain above Max for the .45-70. Max is running about 1,007 FPS at 25,600 CUP out of a 24" TD. It's 4 full grains below minimum(18.0) for the .458 Win with a cast 405. The minimum load runs 1040 FPS.
The speed of sound is 1,126 FPS. So both of your unsafe loads are already subsonic. So are published safe loads.
I know a No.4 Lee-Enfield can be bubba'd into a .45-70, but I suspect you'll find a .458 Win is too long.
In any case, the ACP's big brother is the Colt. And you'd still need a .452" barrel, a proper action wrench and barrel vice.
 
T.O'Heir said:
14 grains of Trail Boss is a full grain above Max for the .45-70. Max is running about 1,007 FPS at 25,600 CUP out of a 24" TD. It's 4 full grains below minimum(18.0) for the .458 Win with a cast 405. The minimum load runs 1040 FPS. 
The speed of sound is 1,126 FPS. So both of your unsafe loads are already subsonic. So are published safe loads.
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You can load whatever fits in the case without being compressed with Trail Boss. So depending on the bullet, magazine length, and throat of the rifle you could easily get 14 grains of TB in a .45-70 or up to 20 grains in a .458 Win Mag. That does not make them dangerous loads with TB just because they are over the max load you found published somewhere. As long as TB isn't compressed it isn't going to do funny things, just load to the base of the bullet like IMR publishes and you'll be fine.

T.O'Heir said:
 I know a No.4 Lee-Enfield can be bubba'd into a .45-70, but I suspect you'll find a .458 Win is too long.
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If you actually read the first and second post by the OP, he didn't want to build his rifle on an Lee. He simply wanted a integrally suppressed magnum rifle or DeLisle esq, he plans to build on a Mauser action. He never had any intention of shoehorning anything into a Lee.
 
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