300 grain and bcg problems

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300 grain and bcg problems

Postby Jumbo 61 » Sun Aug 18, 2019 1:01 pm

I see there's not a whole lot of active subjects on here but will ask this any way. Has anyone had BCG and feeding problems when reloading using 300 grn. XTP Mag. Bullets? They basically turn my gun into a single shot, I even shot video of the bcg and it won't even go far enough back to get the shot round to even clear the ejection and just puts it back in the chamber any ideas would be appreciated!
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Re: 300 grain and bcg problems

Postby Al in Mi » Mon Aug 19, 2019 4:40 am

welcome aboard.

Give us some details on your gun and loads, I'm sure somebody will have a fix for it.
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Re: 300 grain and bcg problems

Postby Bmt85 » Mon Aug 19, 2019 7:32 am

Sounds like you are undergassed.

As Al said, we need details.
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Re: 300 grain and bcg problems

Postby plant_one » Mon Aug 19, 2019 11:12 am

does the upper cycle factory ammo?


also please include details as to which buffer and spring setup you're running.
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Re: 300 grain and bcg problems

Postby Jumbo 61 » Mon Aug 19, 2019 5:17 pm

The 250 grain XTP's ran fine, the buffer/spring Set up is standard as to it came with the stock. The 2 loads I have tried so far AA #9 chrono's @ 1785 and H-110 1660 oal was in the cann. groove and used a medium crimp with the Lee Factory Crimp Die. The gun is all Aero with an 18" bbl. mid gas system don't remember were the bcg came from.
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Re: 300 grain and bcg problems

Postby Bmt85 » Mon Aug 19, 2019 6:28 pm

What were your charges?

AA9 is a pretty fast powder for 450B, might be why that doesn't cycle.
The 296 load seems a little slow, maybe you need to bump the charge up a little.

Have you seen any pressure signs, case head growth in particular?
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Re: 300 grain and bcg problems

Postby Jumbo 61 » Mon Aug 19, 2019 7:35 pm

No pressure signs and I was wondering how the different speeds of powders affect this caliber in a gas system I have not tried bumping up the 110 and I do have other powders that I have seen load data on in this caliber.
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Re: 300 grain and bcg problems

Postby plant_one » Tue Aug 20, 2019 12:07 am

Jumbo 61 wrote:The 250 grain XTP's ran fine, the buffer/spring Set up is standard as to it came with the stock. The 2 loads I have tried so far AA #9 chrono's @ 1785 and H-110 1660 oal was in the cann. groove and used a medium crimp with the Lee Factory Crimp Die. The gun is all Aero with an 18" bbl. mid gas system don't remember were the bcg came from.


i dont know how much reloading experience you have, but it sounds like you could be relatively new to the hobby. please forgive me if this is inaccurate, but thats where my response is geared toward.

generally speaking, when dealing with giving reloading load data someone trying to help you is going to need the following information. the more precise your measurement and data are, the better.

1) brass type (headstamp), trim length is a bonus measurement. likewise for # of times fired.
2) primer
3) powder type and quantity (weight in grains)
4) bullet
5) cartridge OAL, measured in Inches, for example 2.065" - which happens to be the recommended OAL for this bullet from hornady. saying you're seated into the cannellure - which on this bullet is approx 0.040" long, makes that a relatively wide measurement range.

providing velocity information while useful, without the other info listed above isnt very helpful. likewise without knowing the ES and SD to go with that avg velocity. temperature is a good bonus data peice. Those numbers are important.


1785, at least according to hornady seems to put you right at the top of the velocity window - and probably charge - for the AA#9

1660 is defiantly slow for h110.


that begs to ask... how did you pick your test charges?

your saying
The 2 loads I have tried so far
leades me to believe that you either used someone elses load data, or just randomly selected a charge from a chart you found somewhere of min/max for that bullet.

most folks work up a ladder - group of charges, usually 3 or 5 of ea charge weight, often in 0.5gr incriments - to test for both pressure and accuracy. and then shoot those charges from low to high, watching for pressure signs as you progress.


for example a ladder may look like this

bullet: hornady 300 xtp, seated 2.065" oal
brass: hornady, once fired, trimmed to 1.695"
primer: rem 7½
powder: h110
crimp: 0.475"

3 rounds each charge
30.4 gr h110
30.9 gr h110
31.4 gr h110
31.9 gr h110
32.4 gr h110
32.9 gr h110
33.4 gr h110
33.9 gr h110
34.4 gr h110 (max published load)


now obviously some calibers are more forgiving than others, and even within a caliber a given powder/bullet choice may be very forgiving... but others may not be as well, so being consistent with a good testing and load developement process is important. Especially if you're using data from some yoo-hoo on the web that you know nothing about. There's no way to know if someone typo'ed a charge and 39.3 grains shouldnt have been 33.9 and you could be in very very dangerous territory with a simple dyslexia moment like that.


again - if you're a relatively experienced reloader, i apologize for being so detailed, but so many who show up on gun boards with problems like yours, giving incomplete data like you did often have very limited reloading experience, or have gotten how-to advice that was less than stellar and often right into the realm of dangerous - and i would rather spend a few extra mins typing out a good example than have you risk ending up injured over either improper and/or potentially unsafe reloading practices.




please give us as detailed info as you can so we can help you move forward and get this round load shooting and cycling for you :)
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