Model 1 Sales 300 whisper upper function problems

[Jason280]

I also just got in the Whisper game. I have a flat top 16", and it appears to be a M1S upper. It functions 100% w/ CorBon 150gr SP's, but it almost seems like it may be getting too much gas. I am going to measure the port tonight and see what the diameter is. I recently loaded some 125gr BT's and 125gr Bergers, but I haven't gotten a chance to shoot anything. I've also loaded 25rds of subsonic 240's w/ AA No 9 and 25rds with H110. I will definitely give an update when I shoot them on Wednesday.

I'm pretty sure I will eventually go with an adjustable gas tube, especially after my supressor paperwork clears.

[jripper]

Update:

I still can not get the model 1 to work with subsonics. It will not work with corbon factory, or with 240 sierras using W296. In fact, I have the 240s all the way up to 1200 fps, and it still does not cycle. Works fine with supersonic 125s, corbon factory and rem 125 psp with 18.5 W296. I may try another powder with the 240s. Any suggestions from anyone? Faster or slower?

[300whisper_newbie]

Jripper,

Sorry to hear about your continued problems. Since the rifle is not auto-loading can you see how far the bolt carrier is coming back? I think my carrier is almost coming back far enough and just missing by a 1-1.5mm. The rounds in my mag are scratched from just below the lip where the carrier stopped and went back into battery. I cycled mine by hand and think she'll cycle as the carrier/upper wear in a little. I'm in Cali until sunday so I could not bring the rifle to play with it here, I'll try to shoot some more next week and report back on my progress.

FYI: I'm loading 220 sierras over 9.1gr of H110.

--Chris

[Quarterbore]

I am curious if you have looked at some of the other variables...

Have you tried other powder combinations? With the 300 Whisper in a semi-auto the problem isn't the velocity of the bullet but instead the amount of gas that is left to cycle the action. It may be that the powder you are using just doesn't have enough Ooommpp to cycle things...

Also, are you using this with a Rifle or CAR stock?
What buffer are you using (ESP if it is a CAR - Std, H-Buffer 9mm)
Have you considered modifying the buffer spring a little to take off some of the weight?

I would try other powder combos first but there are a couple other areas that could be changed in this system if needed...

[300whisper_newbie]

Originally Posted by Quarterbore

I am curious if you have looked at some of the other variables...

Have you tried other powder combinations? With the 300 Whisper in a semi-auto the problem isn't the velocity of the bullet but instead the amount of gas that is left to cycle the action. It may be that the powder you are using just doesn't have enough Ooommpp to cycle things...

Also, are you using this with a Rifle or CAR stock?
What buffer are you using (ESP if it is a CAR - Std, H-Buffer 9mm)
Have you considered modifying the buffer spring a little to take off some of the weight?

I would try other powder combos first but there are a couple other areas that could be changed in this system if needed...

QB,

I haven't thought about the buffer spring untill you mentioned it. I'm running my 300 whisper upper with a full length rifle stock/tube. I don't have a CAR lower but a buddy has an m4gery that I could borrow his lower to see if that helps at all. I would be interested to see if jripper is also running with a full length rifle buffer.

--Chris

[jripper]

Latest Update:

I got my Model 1 to function with 240 sierras and AA 1680. It was SSK's reccomended load. I am using a full stocked lower, but am using a reduced power buffer spring, made by Wolff, available through Brownells. However, I think it will work with the load with the stock spring. It looks like slower powders are better. I tried AA #9 and W296, and could not make either one work with either load (W296 load did pick up a new round one time, and will actually work the bolt forward and back, but does not pick up a new round, in other words, very close to working).

I also have a m4 stock, but do not have a lower to put it on yet (Indianapolis gun show is coming soon!!!) so I can not comment on that making a difference.

My loads with the AA 1680 only Chronographed 850 fps, so I will be able to bump up my charge a little. (outside temperature was only 39 degrees, and very damp). I would think that any slower powders would probably work, also. I suppose the pressure peak is farther down the barrel with the slower powders.

This does not bother me a bit. I can live with subsonics with only certain slower powders, if it keeps me from going to the hassle and expense of moving the gas port back to the pistol position.

I'll load up some more round with 1680 and see what I can accomplish.

After I finish these 240's, I plan to get some Sierra 220s, to work with. With the W296 load, they were not stablizing in my gun, even though model 1 says it has a 1 in 8 twist. The 220 corbon load, seemed to stalize OK, but the 240's were going into the target sideways at 25 yards.

I did not shoot any of the 240s with the other powders at a target, so I can not say if they would be any different than the 296 rounds, but I don't see why they would be.

I 'll keep posting as I make progress. I am also working on a load with the 296 and 168 BTHP. SSK claims that can make 1950 fps, and if they do, they will make IPSC/USPSA rifle major power factor.

If they do so safely, there could be a whole new market for this round.

Joel

[Zed Stewart]

I would imagine that 850 is to slow to stabilize the 240s. What I have gathered from all sourses is that the 240s are just stable enough to work, at range, with a 1-8" twist. this is why JD Jones says they kill stuff a lot better than the paper ballistics would indicate. (More on that later.) I wouldn't give up on them until you run some at at least 1000 fps.

Just my 2 cents.

[sharpshooter33]

Hi all,
I have had my Model 1 300 Fireball for about 9month. Only have about 15 rds thru it. All rounds are 150gr Corbon. The 1st two or three didn't quite function the bolt but since then I've adjusted my Adjustable gas tube and it's functioned great.

I haven't tried the subsonic yet. Was waiting until I had good barrel breakin.

I am interested now if it will function with the subsonic since I've read this.

My plan is to suppress it this year and I'm looking a Lauer Weaponry right now. Wonder if the suppressor will affect the function also?

I may go out this week and run 5 rounds check with subsonic and check my function.

Also liked the full auto 300Whisper video posted on QB website! :lol:

[sharpshooter33]

Well, I'm glad QB told me to check the forums here. I went to the range today and fired 4 rounds of 220gr Corbon Subsonic. I quit at for because I figured why waste ammo until I got it fixed. My Model 1 I purchased last year some time around summer. I purchased barrel only and put it together my self with upper and adjustable gas tube.

I've now fired 20 rounds of 150gr Corbon without flaw except for the 1st 2 rounds. I use a M16 bolt carrier which is heavier than the AR15. Standard stock and buffer setup. I was concerned originally thinking I may not have lined up my gas port with the block. I'm using a rail fron gas block with locking screws and I wasn't sure that I was getting it exactly over the hole. I have not gaged my port, however after reading this thread I'm thinking I will. I took 5 rounds of 220gr Subsonic to the range and fired them for effect. 1st one almost pulled the bolt back half way. Most didn't pull it enough to remove the case from the chamber. It was about 20 degrees out side and I forgot my allen wrench to adjust the gas system so I didn't stay around the range and tinker with it. I was pretty much convenced by the posts here it would be useless anyway. I'm going to go back and check the hole size and make sure the gas block is aligned properly. Jripper looks like he has had more trouble than most getting his M1 300/221 to work.

Just thought I'd drop a line here and welcome myself to the club.
:shock:

[jripper]

I found some very good information of AR15barrels.com. A retail sight that sells manufactures/sells 300-221 barrels. I believe it is under his FAQ sections, where he states that he also opens up his gas ports to .120, and says that most .223 barrels are around .080. He also says that if the customer wants to use the barrel to shoot subsonics, he puts the gas port at the pistol position, to allow use of all types of ammo.

Opening up the gas port is not that big of deal, as I previously posted.
To move it involves TIG welding the old hole shut, re-drilling the hole in the pistol position (which I am not sure exactly where that is), modifying or replacing the gas tube. You then have to make sure your gas block is going to fit under your handguards (modify or replace most likely). Then, if using a free float, you will have to drill a hole into the handguard to access your adjustible gas system.

There are a few other possibilities that may help. I have tried a reduced power Wolff buffer spring, altough in my case, it did not seem to make much difference(if the loads are real close to cycling, it may help). These spring cost less than $10 (for the rifle length buffer. I still haven't tried my with a CAR stock and buffer, as I am still trying to get a second lower).

JP makes a lightened bolt carrier, that may make cycling easier, and help the loads to work (caution though, use the tactical carrier, and not the match carrier (I believe it is aluminum) as it is only for use with the JP trigger/lightened hammer set). These are $100 plus, and I have not tried them myself, but JP makes excellent products, and have top notch customer service.

There is also a product called a pig tail gas tube. I don't know who makes them, but Brownells sells them. They are supposed to lengthen the pressure curve. This might also help, as I previously posted, I have had luck with slower powder and subsonics. These are $80 plus.

AA 1680 seems to work with subsonics for me, and that if fine, as I primarily want the gun to function with supersonics, as Illinois makes getting a supressor extremely exspensive, if not almost impossible.

My bolt also has broke in quit a bit, and I have not tried the Corbon Subsonics since then, as I shot all but one single round. I can not tell if they would now work.

If you reload, try some loads with the AA1680, or slower powders, unless you absolutely have to be able to shoot factory corbon subsonics.

I suspect that you will have to open the gas port, regardless.

Good luck. Keep posting, as will I, and we will compare our progress.

By the way, I was shooting sub 1/2 inch groups with remington bulk 125 gr psp at 50 yards, and pretty sure it will shoot 1 moa at 100, but was using a Holosight, and the best I could keep them in was 1 1/2 inches.

This is plenty good enough for a 325 upper assembly.

Joel